Plz help


In Runtime
I downloaded ATI tool to OC my GPU its a x1950pro and somehow the memory got set on like 1363 and the core is like 574 or something wich is fine but I cant get the memory to go down everytime I try to restore the defualts it just goes black and then goes back to a error screen saying it has timed out or it just stays black. Now the HUD in CS is fuzzy and when I startup it shows my background but my icons and start bar doesnt show up for like 5 minutes literally. Plz help me guys.