Mac crashing with black screen on XCode install + random other times

I have a Macbook Pro bought over a year ago without extended warranty.

Lately it has started crashing as follows - the screen goes black. The last note of the music (if playing, radio or iTunes) loops repeatedly. It will not go into in standby when screen is closed. Power button will not shut it off, unless held for four seconds.

This started happening very often (several times a day) last week, so I updated to Lion from Snow Leopard. It has not helped at all.

I attempted to uninstall any 3rd party pref panes (memory manager, finderpop). Shut off all login programs from system preferences -> users.

Today I attempted to install Xcode 4 from the App store. I hit next, and the computer crashed.

Rebooted, shut off every running program (far as I can tell, but I'm no pro), tried again. Computer crashed. Rebooted, uninstalled Xcode 3, shut down regularly. Held power button for ten seconds with power plug disconnected. Rebooted. Tried again. Boom.

So, I finally have a consistent way to find the issue, but its a serious issue. Please, please, someone help me figure out what is causing the laptop to be so unstable?

Could not find anything useful on Mac forums or elsewhere. Cannot justify buying a new laptop. At all.

Below is the err report from the last bootup. I notice the high panic count.

Interval Since Last Panic Report:  35463 sec
Panics Since Last Report:          4
Anonymous UUID:                    00AD0027-2B0C-4F7D-BCA5-390795E6F961

Tue Dec 27 16:09:00 2011
panic(cpu 0 caller 0xffffff7f809e800b): NVRM[0/1:0:0]: Read Error 0x00000100: CFG 0xffffffff 0xffffffff 0xffffffff, BAR0 0xc0000000 0xffffff80a06b1000 0x0a5480a2, D0, P3/4
Backtrace (CPU 0), Frame : Return Address
0xffffff807cc43800 : 0xffffff8000220702 
0xffffff807cc43880 : 0xffffff7f809e800b 
0xffffff807cc43910 : 0xffffff7f80ad8120 
0xffffff807cc43960 : 0xffffff7f80ad81e0 
0xffffff807cc439c0 : 0xffffff7f80d84749 
0xffffff807cc43b00 : 0xffffff7f80af7269 
0xffffff807cc43b30 : 0xffffff7f809f196e 
0xffffff807cc43be0 : 0xffffff7f809ed270 
0xffffff807cc43dd0 : 0xffffff7f809eed25 
0xffffff807cc43eb0 : 0xffffff7f80989b88 
0xffffff807cc43f00 : 0xffffff7f820a67d6 
0xffffff807cc43f50 : 0xffffff7f820a6f2a 
0xffffff807cc43f70 : 0xffffff800023db2c 
0xffffff807cc43fb0 : 0xffffff8000820057 
      Kernel Extensions in backtrace:
         com.apple.NVDAResman(7.1.4)[71EBC846-807C-386D-8D01-E144A87FAC0F]@0xffffff7f80987000->0xffffff7f80c60fff
            dependency: com.apple.iokit.IOPCIFamily(2.6.7)[6D54F06A-46B7-37FC-AF22-DE68DC18A1A3]@0xffffff7f8083e000
            dependency: com.apple.iokit.IONDRVSupport(2.3.2)[6517D9A6-58F5-3CFC-B021-C882306150D5]@0xffffff7f80975000
            dependency: com.apple.iokit.IOGraphicsFamily(2.3.2)[55FF26D3-292D-3B4B-8AB7-1D25C8B4313B]@0xffffff7f8093d000
         com.apple.nvidia.nv50hal(7.1.4)[A44D0B74-5A18-34D5-842C-4E280365F55F]@0xffffff7f80c61000->0xffffff7f80f82fff
            dependency: com.apple.NVDAResman(7.1.4)[71EBC846-807C-386D-8D01-E144A87FAC0F]@0xffffff7f80987000
         com.apple.driver.AGPM(100.12.42)[8F3B9F67-D208-326F-97D6-65E3ECF70B37]@0xffffff7f820a5000->0xffffff7f820affff
            dependency: com.apple.iokit.IOGraphicsFamily(2.3.2)[55FF26D3-292D-3B4B-8AB7-1D25C8B4313B]@0xffffff7f8093d000
            dependency: com.apple.iokit.IONDRVSupport(2.3.2)[6517D9A6-58F5-3CFC-B021-C882306150D5]@0xffffff7f80975000
            dependency: com.apple.iokit.IOPCIFamily(2.6.7)[6D54F06A-46B7-37FC-AF22-DE68DC18A1A3]@0xffffff7f8083e000

BSD process name corresponding to current thread: kernel_task

Mac OS version:
11C74

Kernel version:
Darwin Kernel Version 11.2.0: Tue Aug  9 20:54:00 PDT 2011; root:xnu-1699.24.8~1/RELEASE_X86_64
Kernel UUID: 59275DFA-10C0-30B3-9E26-F7B5DFB1A432
System model name: MacBookPro6,2 (Mac-F22586C8)

System uptime in nanoseconds: 127877788781
last loaded kext at 30972810494: com.apple.driver.AppleHWSensor 1.9.4d0 (addr 0xffffff7f81ebb000, size 28672)
loaded kexts:
com.rim.driver.BlackBerryUSBDriverInt   0.0.68
com.apple.driver.AppleHWSensor  1.9.4d0
com.apple.driver.AppleMikeyHIDDriver    122
com.apple.driver.AudioAUUC  1.59
com.apple.driver.AppleUpstreamUserClient    3.5.9
com.apple.driver.AppleMCCSControl   1.0.26
com.apple.driver.AppleTyMCEDriver   1.0.2d2
com.apple.driver.AppleHDA   2.1.3f7
com.apple.driver.AppleMikeyDriver   2.1.3f7
com.apple.driver.AGPM   100.12.42
com.apple.driver.AppleIntelHDGraphics   7.1.4
com.apple.driver.AppleIntelHDGraphicsFB 7.1.4
com.apple.driver.SMCMotionSensor    3.0.1d2
com.apple.iokit.IOUserEthernet  1.0.0d1
com.apple.driver.AppleSMCLMU    2.0.1d2
com.apple.GeForce   7.1.4
com.apple.Dont_Steal_Mac_OS_X   7.0.0
com.apple.driver.AudioIPCDriver 1.2.1
com.apple.driver.ACPI_SMC_PlatformPlugin    4.7.5d4
com.apple.driver.AppleMuxControl    3.0.16
com.apple.driver.AppleLPC   1.5.3
com.apple.driver.AppleBacklight 170.1.9
com.apple.filesystems.autofs    3.0
com.apple.driver.AppleUSBTCButtons  225.2
com.apple.driver.AppleUSBCardReader 3.0.1
com.apple.driver.AppleUSBTCKeyEventDriver   225.2
com.apple.driver.AppleUSBTCKeyboard 225.2
com.apple.driver.AppleIRController  312
com.apple.iokit.SCSITaskUserClient  3.0.1
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1
com.apple.BootCache 33
com.apple.driver.AppleUSBHub    4.5.0
com.apple.iokit.IOAHCIBlockStorage  2.0.1
com.apple.driver.AppleFWOHCI    4.8.9
com.apple.iokit.AppleBCM5701Ethernet    3.0.8b2
com.apple.driver.AppleEFINVRAM  1.5.0
com.apple.driver.AppleSmartBatteryManager   161.0.0
com.apple.driver.AirPort.Brcm4331   512.20.18
com.apple.driver.AppleAHCIPort  2.2.0
com.apple.driver.AppleUSBEHCI   4.5.0
com.apple.driver.AppleUSBUHCI   4.4.5
com.apple.driver.AppleACPIButtons   1.4
com.apple.driver.AppleRTC   1.4
com.apple.driver.AppleHPET  1.6
com.apple.driver.AppleSMBIOS    1.7
com.apple.driver.AppleACPIEC    1.4
com.apple.driver.AppleAPIC  1.5
com.apple.driver.AppleIntelCPUPowerManagementClient 167.0.0
com.apple.nke.applicationfirewall   3.2.30
com.apple.security.quarantine   1
com.apple.driver.AppleIntelCPUPowerManagement   167.0.0
com.apple.driver.AppleHDAHardwareConfigDriver   2.1.3f7
com.apple.driver.DspFuncLib 2.1.3f7
com.apple.driver.AppleSMBusController   1.0.10d0
com.apple.iokit.IOSurface   80.0
com.apple.iokit.IOBluetoothSerialManager    4.0.1f4
com.apple.iokit.IOSerialFamily  10.0.5
com.apple.iokit.IOAVBFamily 1.0.0d22
com.apple.iokit.IOFireWireIP    2.2.4
com.apple.driver.AppleHDAController 2.1.3f7
com.apple.iokit.IOHDAFamily 2.1.3f7
com.apple.iokit.IOAudioFamily   1.8.3fc11
com.apple.kext.OSvKernDSPLib    1.3
com.apple.driver.ApplePolicyControl 3.0.16
com.apple.driver.AppleSMC   3.1.1d8
com.apple.driver.IOPlatformPluginFamily 4.7.5d4
com.apple.driver.AppleGraphicsControl   3.0.16
com.apple.driver.AppleSMBusPCI  1.0.10d0
com.apple.driver.AppleBacklightExpert   1.0.3
com.apple.nvidia.nv50hal    7.1.4
com.apple.NVDAResman    7.1.4
com.apple.iokit.IONDRVSupport   2.3.2
com.apple.iokit.IOGraphicsFamily    2.3.2
com.apple.kext.triggers 1.0
com.apple.driver.BroadcomUSBBluetoothHCIController  4.0.1f4
com.apple.driver.AppleUSBBluetoothHCIController 4.0.1f4
com.apple.iokit.IOBluetoothFamily   4.0.1f4
com.apple.driver.AppleFileSystemDriver  13
com.apple.driver.AppleUSBMultitouch 227.1
com.apple.iokit.IOUSBHIDDriver  4.4.5
com.apple.driver.AppleUSBMergeNub   4.5.3
com.apple.iokit.IOSCSIMultimediaCommandsDevice  3.0.1
com.apple.iokit.IOBDStorageFamily   1.6
com.apple.iokit.IODVDStorageFamily  1.7
com.apple.iokit.IOCDStorageFamily   1.7
com.apple.driver.XsanFilter 403
com.apple.iokit.IOAHCISerialATAPI   2.0.1
com.apple.iokit.IOUSBUserClient 4.5.3
com.apple.iokit.IOFireWireFamily    4.4.5
com.apple.iokit.IOEthernetAVBController 1.0.0d5
com.apple.iokit.IO80211Family   411.1
com.apple.iokit.IONetworkingFamily  2.0
com.apple.iokit.IOAHCIFamily    2.0.7
com.apple.driver.AppleEFIRuntime    1.5.0
com.apple.iokit.IOHIDFamily 1.7.1
com.apple.iokit.IOSMBusFamily   1.1
com.apple.security.sandbox  165.3
com.apple.kext.AppleMatch   1.0.0d1
com.apple.security.TMSafetyNet  7
com.apple.driver.DiskImages 331
com.apple.driver.AppleKeyStore  28.18
com.apple.iokit.IOUSBMassStorageClass   3.0.0
com.apple.driver.AppleUSBComposite  3.9.0
com.apple.iokit.IOSCSIBlockCommandsDevice   3.0.1
com.apple.iokit.IOStorageFamily 1.7
com.apple.iokit.IOSCSIArchitectureModelFamily   3.0.1
com.apple.iokit.IOUSBFamily 4.5.3
com.apple.driver.AppleACPIPlatform  1.4
com.apple.iokit.IOPCIFamily 2.6.7
com.apple.iokit.IOACPIFamily    1.4