i just had my ibm thinkpad wiped clean by a computer tech, i've got AVG installed and had just scanned for virus' and there was no threats. after the scan, my mouse stops working, so I restarted it, and now it just keeps rebooting going to a blue screen with white text saying the laptop wasn't shut down properly and to reboot
First try uninstalling AVG since the problem seems to have occurred after it was installed. See if that helps.
Something could have gone wrong during the installation of Windows which is causing your issue. Or there may have been an update that did not install properly and caused the issue.
It is very remote, but it did happen to me several years ago. I wiped my PC and re-installed Windows XP, and installed some updates. The PC became unstable. I wiped the PC again and installed the same updates and everything was fine.