ATI 8.12 driver problems

Every time i try to install ati 8,12 drivers it starts the installation and finish but then when i press finish window's tell's me it's a bad driver or that it wasn't installed properly.I have tryed removing 8,11 all together and just installing on top of 8,11 nothing work's.I have DL'ed it 4 different time's with no luck,3 of the time's from the ati DL site.Is there anyone who has had such a problem and fixed it?
It only seem's to be a problem with 8,12 because after removing 8,12 i put 8,11 back on with no problem's.

Try running CCleaner (http://www.ccleaner.com/download/downloading)to get rid of the cache

Thanx,i have CCleaner i will give it a try next week a friend has a copy of 8,12 that worked on his vista 64bit machine so i am going to get his copy and then i will try again and i will run CCleaner aswell and cross my finger's.