wierd problem on x50v w/ SE

I just starting having a problem with my x50v (2003SE) where I'll go to use it and it will be really hot and the battery will be drained. It's happened twice recently but never before. Any suggestions or ideas? Thanks!

[Gigi]

Was the wifi left on by accident? Was a video left running in the background? Try a soft reset before powering OFF to see if the problem persists.

neither. i've had various pda's over the years but this is new to me (though i've heard of it from folks who upgraded from 03se to wm5). hmmmm..... only thing new is airislands.