Ati problems please help

[martifs]

Hello,

i have a 4870 i use with 2 monitors, it has just recently decided only to work for one and only the 2 from either port. any ideas. also while i can run some games and apps. when i get really intense graphics situation. it start showinf negative images and alot of artifacts

 

[disaster101]

is it overclocked is any of your other components overclocked? and how old are your parts

 

[jeepster50]

It could be overheating, maybe a good cleaning is in order. What temps is it running at?