In all honesty, given the information you give they haven’t a hope of correcting any fault, assuming that it is avast related.

I have had to uninstall avast on a number of occasions and never had a problem with an XP crash, or do you mean BSOD ?

However, I bought this system just over two years ago and I purchased XP Pro (with SP3 incorporated), so I haven’t seen this. But if it were a common issue with XP SP2 then no doubt there would be more posts about this than this one.

If it is a BSOD then you need to send the minidump files and or memory.dmp file to avast for analysis, if a) this was recent and b) if you still have them ?