This is weird...

I went to bed around 1:30 a.m., with my computer on, playing SG-1's "Flesh and blood". When I woke up, the monitor was turned off, and not because it was saving power, but because the button was pressed. The program I used to play the file was also turned off...
I was alone in my apartment and the cat is not allowed to the bedroom while I sleep (not to mention that it's virtually impossible that he actually did it).

Was I sleepwalking?

Any ideas?...