Yes, I see all of the instup.exe activity. These logs get massive and there isn't much in the way of housekeeping, so periodically I will clear them.
Whilst the Repair says it sets things back to default installations, I find that it doesn't, especially for avast.ini changes that you have made.
I'm less concerned about XP end of support than all of the cr4p about doom and gloom come 8th April 2014. My computer hasn't blown up nor become infected. Whether you get infected or not also depends on the user, practising safe hex, and having good security based software, using proactive measures. I still use DropMyRights for all internet facing software, browsers, email clients, etc. etc. to try to limit and potential damage should I ever get infected (not for ten years on avast).
Strangely/interestingly enough my last infection was shortly after installing XP and going on-line to get the updates, I was using A V G then and not long after that I changed to avast.
If all else fails ensure that you have a robust backup and recovery strategy. I predominantly use drive imaging software (weekly partition backups) and I have used many, many times over the years, not once for a malware infection. If I experience a problem that is likely to take more than 30 minutes to resolve I just restore my last weekly image.
When you consider the number of XP users that are still on SP2 (some possibly on SP1), they haven't had security updates for some considerable time.