I have a ATI Radeon 7500 in my inspiron 8100.

Just recently when booting up my computer the screen is all garbled with colored bars and squares that flicker and change.  Nothing is readable therefore I cannot get into windows.  This only happens after the computer has been on for a couple minutes and gets warm.  when cold, it usually starts fine but after a few minutes bars start to fill the screen. 

I have heard a lot of people are experiencing this problem after updateing their graphics chip bios and or updating its drivers.

I have no clue on how to fix this... please help.