>I have a PC that I think is infected with a virus. The symptom is that I cannot get it booted up into Windows XP. It keeps saying
>
>svchost.exe - Application Error
>
>An attempt was made to execute an illegal instruction.
>
>I downloaded a program to use to fix it, supposedly, but if you can't even boot up the machine, how do you then use a program to fix the problem? Catch 22 situation.

A couple of possibilities:

1) get current a linux/Knoppix Live CD or DVD. Writing to NTFS for a dozen files is no problem, most of them can handle NTFS full time.

2) Get a Windows LIVE CD - there were some CD's with MS virus scan about 18 months ago on the market. For single operations very nice.

3) Build your own Windows Live CD from XP Disk and PA builder. You'ld need a second system or a buddy who already has it.

4) there are emergency disks on the market to fix HD problems, also to check under Linux vor WIN-viruses.

5) If you have a second disk, write a copy of a running system to it (using one of the emergency disks and a friend with a running system), hang that disk into your PC and boot from there. Your old disk should be available as well and you can fix from there.

6) Install the second HD without OS and create another OS install on it making the machine a multi-boot.
Boot second OS and fix. Added benefit: safety if the other OS fails.

7) Use you Original CD to repair the OS install. Usually (in case of partition table/directory trouble) the very last option, as it might make things worse. In your case perhaps not so bad if it is only one rotten file.

My list of preferences in desc order : 6, 5, 1, 3, 2, 4 and in real need even 7.
If valuable data is on the disk, get a cheap one and make a full sector copy using a emergency disk in the night before going to work on the original.

XII : golden rule: think before *every* step and don't panic.

HTH

thomas