fix computer errors

Hi,
I keep getting the blue screen when I try to load my computer through normal settings. It crashes with a blue screen at the “Windows Vista” loading screen with the bar, and then restarts, and then repeats. This was after I used System Mechanic to “optimize” my system by compressing the registry, optimising memory useage and defragmenting the drive (although I cancelled defragmentation mid-way). It keeps crashing over and over, or loads the desktop with just a black screen. When I try to use the Task Manager, it tells me that the application failed to initialize.
The error message that I’m getting on the blue screen is:
“disk.sys
DISK_FAULT_IN_NONPAGED_AREA”
It then does a “memory dump” before restarting, and doing the same thing over and over.
I have Hiren’s Boot CD 9.8, but I don’t know which programs to use to get it back. I’d like to try some methods rather than factory resetting my computer.
Can anyone help? Or suggest programs to use on Hiren’s Boot CD? Or even any alternate suggestions?
Thank you in advance.
NOTE: I posted up this question before, but I wanted to add more details. Just to make this clear, I cannot use System Restore because it was turned off prior to a previous virus attack. Also, starting the computer using the “Last Known Good Configuration” doesn’t seem to help. Right now, I can only load it in Safe Mode.