Windows 7 64-bit installation freezes after a while during the setup

I have Windows 7 32-bit on my computer. Because I have 5GB of RAM (Kingston) on my Asus M2N motherboard and only 3GB were able to be used, I bought Windows 7 64-bit and installed it. It loads the wizard, but after a while, it freezes, and I have to force reboot. It first crashed while unzipping Windows 7 files, but if I wait a while on the terms page for example, it can crash before, which make me think that it is a matter of time. I remember I had the same issue while booting on Ubuntu 64-bit, it crashed randomly but not load completely. No beep or other messages.

Configuration:

• Software
  • OS (before) Windows 7 Professional 32-bit
  • New OS: Windows 7 Professional 64-bit
  • Antivirus: Avast (BIOS verification?)
  • BIOS; 03/27/2008 - v08.00.12
• Hardware
  • Motherboard: Asus M2N
  • Processor: AMD Athlon 64 dual core 2.6 GHz
  • Memory: 5120MB ((2 + 2) + (1))

NOTES I ran a memory test using openSUSE CD, though I have not finished it, it ran.

EDIT: I tried not to run the setup but wait, and I get a BSOD

A problem... TL;DW

IRQL_NOT_LESS_OR_EQUAL

If it is... TL;DW

***STOP: 0x0000000A (0x0000000000000000,0x0000000000000002, 0x0000000000000001, 0xFFFFF8001A49ED1F)