problems with "up"

Is anyone else having this trouble? very randomly my PSP starts going up, as if the button is stuck but I cant get it to stop. I'm not sure if it's software or hardware related.
I'm just worried that it could be a virus or some glitch. It comes and goes but has been getting more frequent.
I cant return my psp because I bought it during my stay in Japan. Any suggestions?

OoO, Japan...
Knowing that the people of Japan suffered of the "X" button. I doubt it's a virus.
Try starting your PSP with the dialog nub facing up, if that does not help, then try it on the control pad also.

It seems the dialog stick on anything Nintendo or Sony related always has trouble.

other than that, I have no idea how to fix this. Sorry.

-James