But you can type in other places, like the Start Menu > Run... dialog box?

Does it happen <i>every</i> time you run Spybot? If so, you probably want to try AdAware first then.

In the end though, with the freezing etc. as well, it's probably a good idea to install a virus scanner and scan the computer, then reformat and reinstall Windows to a clean installation then put the virus scanner on again.

Might be good to check all the cabling is securely plugged in like the keyboard, power supply etc. and the fans at the rear have plenty of ventilation space.