I just upgraded from a GTX 470 to a Radeon 6950. Installing drivers for the new gpu went fine, zero problems. I then started removing my old Nvida drivers and other options. This is where I hit my problem.
I downloaded an option for monitoring gpu tems with the nvida monitor / performance options now when ever I go to uninstall those two items (the last two remaining) I get a 1628 error code (unable to uninstall program).
and on boot up I get a kdbsync.ex - System Error
"The program can't start because OpenCL.dll is missing from your computer. Try reinstalling the program to fix this problem."
I've tried googling the issue and error codes but really I only find people asking similar questions on the Nvida forums or other rando websites and those people don't ever seen to get a straight forward answer.
I don't know of any long-term ramifications of simply ignoring the prompt every time I start up, but its rather annoying.
I believe I was finally able to remove Ntune from my PC as there are no more folders remaining on any of my drives and I tried running CCleaner to fix all my registry problems, etc.
I suppose you'll have to reinstall windows to fix all your problems. Even if you manage to fix it somehow, it will only be a temporary fix and it will emerge again soon enough. These kind are problems are annoying, and have only one solution.