Avast randomly shutting down my PC?

Well, i don’t know if it’s avast fault really. But i’ll describe the problem here, maybe some people are experiencing the same or maybe some ppl can help me even if it isn’t avast’s fault

My computer has been running rock solid for a year, then i decided to use switch my AV to avast!, since then my computer randomly shuts down. It may stay on overnight, but when i’m working on it, sometimes it just shuts down. I have to turn off and back on the power supply in order to turn on the machine again, it won’t do it otherwise. Power supply voltages are running normal whenever i check them.

Some other similar problem is when i lock the station, then another person logs in another with WinXP account then when this person logs off, the computer is still running but the monitor displays nothing (input signal from monitor is OK, green)!

May this be related to avast? I’m just posting this here cause all this started happening after i installed avast, but may not be related to it. I’ll try uninstalling and see if the problems still persist.

I’m not sure if the problem is directly related to avast, but you say you switched AVs. What was your previous AV and how did you remove it. Two resident AVs can cause conflict and lock up your system, but not to shut it down or is it a crash?

Are you getting any warnings/errors at startup?

Previous AV was AVG. Uninstalled trough its own uninstaller.
I’m not getting any warnings.

Is the avast icon in the system tray and is avast running ok prior to the shutdown?
How does the computer shut down, crash or is there a warning, computer will shutdown in 30 secs, etc?

Do you have any other security software that runs in the background?

If you try an uninstall reboot and install reboot, watch for any warnings during install.

It will be useful if you search the Registry to see if AVG (or Grisoft) keys were left behind…

What do you mean? Error messages or infection warnings?