Windows Vista Won't Start

OK. I hope I'm on the right board.

I have a Dell Dimension 9100.
BOIS - A01 (5/25/05)
Intel 4 CPU 3.00 Ghz
2.0 GB Memory
533 Mhz Speed
DRSDRM

Hope this helps.

Anyway, I upgraded from XP to Windows Vista Home Premium a couple of months
ago. Things had been running a little strangely, but nothing that I figured
couldn't be considered part of a new OS.

Until this week. When my PC crashed with the blue screen of death. I've
tried to restart the computer with the Windows Vista disc and it often will
repair successfully and work for a few minutes, even a few hours, then crash
again.

I have recorded the following error messages during the course of the
restarts (forgive me if I've written down some of the info partially).

"Failed checkpoint Ithr"

"Unknown bugcheck. Bugcheck d1 Parameters=0x18,0x2,0x0,0x81f3a261"

"ACLs on file c:\\windows/system32/KGYGaAuL.sys not proper. Old value =
0x12019f access control repair successful"

"ACLs on file c:\\windows/system32/7A4889384B.sys are not proper. Old value
= 0x12019f Access Control Repair successful"

I'm at wit's end (actually just outside of Atlanta).

Any ideas?

Thanks,

Reed Barker
reedbarker*comcast.net