Fresh Windows install and suddenly, no 120 Hz, only 60 HZ

[dwbradley]

Hey guys,
I have been going 'round and 'round with this problem for several days and I am ready to run up the white flag. Maybe you can help with some suggestions.

Basis of the problem: A few months back I fumble-footed a power cord, causing a power bounce on my sim-racing rig. There was some file-corruption in Windows. I identified a few files that I corrected and everything seemed OK (mostly). I get some odd crashes now and then and I have begun to worry about the drive itself. One symptom is increased noise, which is worrisome.

So, I determined that this last weekend was a good time to do a fresh Windows install on a new disk and have a clean environment. All went well until I tried setting up Eyefinity for my triple-screen. It will not let me have 120 Hz for a triple screen option. Two monitors (the ones on DP), yes. Three, no.

Now here is the crazy part. If I boot from the old disk, all is hunky-dory. 120 Hz, triple-screen Eyefinity, no problem. Boot from the new, no way. So, almost certainly not a hardware issue.

I have uninstalled and installed Catalyst (of several vintages) to no avail.

I have fiddled with Windows screen resolution choices until I am sick of seeing those screens

I have taken away the drivers (.inf) and re-installed many times.

I have looked at the .inf files. Interestingly, there is a folder buried deep in \Windows\system32\........ that has the .inf file and three other files. I did a compare of the files and three of them are identical. The fourth, xl2420t.PNF (file type is decoded as a pre-compiled setup information file) is different. I thought, well, let's try overwriting the new .PNF with the old one. So far, Windows has proven far stronger than I at keeping me from changing the permissions that will let me copy to this folder. Any advice here would maybe be a way to unlock this puzzle.


My system:
Core i52500K
8 Meg Ram
2 X HD7970 in Crossfire
3 X BenQ XL2420T monitors (two with DP, one with DVI)
Window 7 Professional (64-bit)
Catalyst version 14.4 on the old disk (120 Hz is fine)
Catalyst version 14.3 beta on the new disk (60 hz only); have had various other versions on, all same

I am hoping that I have simply overlooked something obvious. I would be happy enough to wipe the egg off my face and continue on my merry way, doing sim-racing not system debug.

I can supply more details but maybe best to supply that which is needed and requested and not just a data dump. This is already getting to be a long sob story

Thanks

Dave Bradley