you have adaware and spybot loaded, but did you run a scan recently?
Also, when I originally read your thread I thought I knew a possible answer, but then you mentioned the USB key.
So.... give us more info.
CD drive.... is it internal or external....if external, what is its interface?
OS .... what OS, service packs/patches current?
BIOS, and other system drivers current (Intel chipset....etc)?
Did you always have this problem? Did it start happening after you moved the comptuer or install software/hardware?
Thanks