Windows Vista Home Basic wont boot up

Hi

I hope you can help me here. For the better part of 3 months now I have had my computer just suddenly shut down show me a blue screen with some writing on it, which i cannot get to read because it goes quickly, and then restart again.

I was able to do what I wanted on the computer normally but it keep shutting down and restarting.

a couple of times it has not restarted completely..and I had to use a windows Vista start-up recovery disc to get it running again.

I have scanned the computer a number of times and found an infection (C:\Windows\system32\Drivers\zypiozoa.sys) and each time I think I have deleted it, days later it appears again.

i do not have access to the Windows Vista Install disc because when I bought the computer it was pre-installed

Then . Now the computer gave me another blue screen and wont start up Windows again. The screen says,

Windows failed to start. A recent hardware or software change might be the cause. To fix the problem 1. Insert your Windows installation disc and restart your computer (This is what I did).

The last part of the screen says,

File:\Windows\System32\Drivers\zypiozoa.sys
Status: 0xc0000225
Info: Windows Failed to load because a critical system driver is missing or corrupt


When I put in the Windows Vista Startup Recover Disc, I get this screen,

StartRep.exe- Application Error

The exception Breakpoint
A breakpoint has been reached. (0x80000003) occurred in the application at location 0x7393764a.

I even tried System Restore for different points and it did not work.

i also tried starting in safe mode and it wont even go there.

Help!