Unstable system with Avast

[Claymore]

I've tried Avast a couple of times over the last month or two, with similar results. in both cases, I downloaded the latest version (268, and 289 last weekend), and installed it after removing AVG. It worked well at first, but then memory use started creeping up, things got slower, and on occasion, while switching from one user logon to another in XP, the system would hang, or would come up with a blank wallpaper (I could bring up task manager and start Explorer manually though). In both cases, I installed Avast, tried it without the email scanner, and even tried stopping the P2P scanner too.

I've had to remove Avast because of this, and reinstall AVG - and then things are back to normal, a nice, quick, reliable machine. I would love to use Avast though - it seems a more comprehensive product, and the program/virus updates are very small, unlike AVG which requires a 1.7MB download every single day.

Any ideas about what could be going wrong? My system specs are:
Athlon 2200XP, 512MB RAM, 60GB HDD with 10GB free, Windows XP Pro with all updates, ISDN 64k dialup.

[Vlk]

Do you use a firewall? An online backup software? Any other low-level stuff?
Also, do you use KazaaLite?

And, does the Task Manager show any memory leaks (i.e. constant grow of used memory)?

Thanks
Vlk

[Claymore]

I do use a firewall - Kerio Personal Firewall 4.04. Hasn't given me any problems. I don't have any other online backup stuff, or other low-level stuff, as far as I know. We do tend to have a lot of applications loaded though - things like YahooPOPs, Hotmail Popper, AC42 (stay connected to the net), often MSN Messenger or Trillian, etc. I have loaded Kazaa Lite, and use it occasionally, but not recently.

Task manager does indeed show memory use growing - but significant amounts only when Avast is loaded. It's hard to pin down though, because we very rarely reboot, and we use a lot of applications.