The last few weeks I experienced a new strange behavior of my computer. Sometimes Windows 7 just freezes with no real reason at all. While listening to music for example the playback hangs and you can hear a very nasty sound. Neither mouse nor keyboard input is handled and everything is just stuck. Using Ubuntu this does not happen, so I think it is just a matter of driver issues or a Windows 7 bug.

Furthermore I am really suspicious about Kaspersky (Internet Security 11) and so I let it perform a complete virus scan while no other app is running. At about 50% it happened again and I needed to restart the computer by holding the power button the bad way...

A really weird thing is that playing Skyrim this happened once, however music playback did not stop. Only the framerate dropped to 0 and sometimes for a few seconds I am able to move. Therefore I am really confused as furthermore no bluescreen pops up.

Memtest told me that everything seems to be alright...

Can anyone explain me which data you need about my hardware and software (and which tools tools to use to gather the informatik) to be able to provide any help on my problem?