Installing AV software on an infected machine

I'm trying to repair a customer's PC that runs Windows 2000 and has at least one or more viruses.

All malware has been cleaned but the virus hooks the file creation calls. Because of this, trying to install Grisoft Anti-Virus program (AVG) makes it fail it's file integrity check because copying it from CD-ROM to the hard disk makes the file become corrupt. The file isn't really corrupt, but the CRC is fucked up because of the additional junk injected by the virus.

I can't make a rescue disk because AVG needs to create that *on* the target machine and I have no other Windows 2000 systems to work with.

I'm not a Linux user (no booting off a Knoppix disc to do repair work) and don't want to swap the HD out or anything like that. I just need some AV software that will run off a CD-ROM or floppy disk without having to install anything - any suggestions?

Reformat to punish him. I do it at work all the time.

Or steal McAfee, that always seems to install fine, even on the most corrupted Winstallations.

www.ultimatebootcd.com - several DOS-based antivirus packages on there. Might want to look up about updating the definition files though (they are about six months out of date, which in virus terms is ancient history).

Of course, if you know what you doing, you can just boot in safe mode, go through the registry and/or msconfig and take out any suspect file entries and their associated executables, then reboot into normal mode where you should have removed or neutered the viruses sufficiently to install and run an antivirus proper to clean up the detritus. Best to have another computer with an internet connection beside you, so you can look up the names of any suspect processes/files.