Need help after clearing "Isass.exe operation failed" error

[Guest KH]

I received the above error which caused my pc to continously reboot itself. I

was able to run an anti-virus program which deleted a "trojan" and some other

"worms" I think.

 

In my haste to resolve this problem I think I also installed a second

Windows XP OS.

 

I now have two problems:

 

1) The two OS appears whenever I reboot. The newly installed OS appears

first. When I click on that I can get to the internet etc but all my

settings, documents cannot be accessed.

2) The second OS (which is my original OS) appears second. When I click on

that the computer continuously reboots but does not resolve itself. I get a

black screen. Then a blue screen indicating that that "settup is restarting"

 

How do I delete the OS that appears first when that is all I can access?

 

How do I resolve the second OS from causing the PC to reboot.

 

Thank you.