Windows Xp stop error

I bought a Thikpad T410 its Core i5 proccesor 4Gb Ram 160Gb hard Disk I wanted to downgrade Win7 to XP But while installation this error occoured 0x0000007B (0xF78D2524, 0xc0000034, 0x00000000, 0x00000000) I know its an INACCESSIBLE_BOOT_DEVICE error But why is this happening is the Notebook protecting itself

Try the steps listed here, it's a common issue. The PC can't talk to its hard drive basically. Could be several causes.

http://pcsupport.about.com/od/findbyerrormessage/a/stop0x0000007b.htm