Gadge said:installed some hp drivers for a printer.
However I'd put my money here.
HP software is absolutely terrible.
People moan at MS, compain about Creative Labs and shout about NVidia.
These companies are god-like compared to the horrible software HP thrown at you.
It's just a shame as their hardware is usually quite good - you just have to hope that there is a generic driver or a "driver only" package available because the rest of the stuff....
Try uninstalling all the HP software and see how you go.
However I've seen plenty of systems where you just cannot get rid of the HP software and you may be stuck with it.