Replying to Computer blue screen

any techies know what to do about this?: every time i turn on my lappy i get blue screened twice, i restart after each and then its fine until it logs off when im done, and then the story repeats. no new hardware or software or drivers installed, reimaged recently but had a really similar problem before. im running xp professional if it helps.... idk who else to really say, if you need more info just ask me. i wanna get rid of this, its pretty annoying