Whats wrong with my graphics card?Help?

Last month i was playing a game called Fiesta Online, and had no problems leaving it running over night. I uninstalled fiesta and reinstalled it this week. Now when i play fiesta,after 10 minutes of it being open, the screen shrinks itself to a small white square. When i use task manager to end fiesta my screen looks really old school with terrible graphics. And i’m talking about my desktop. Please help i don’t know whats wrong with my computer,I’ll post screenshots if necessary. (And by the way i’m using a very small notebook, windows xp home edition build 2600 [HP]. It’s one of those tiny tiny notebooks if it helps.)