Thank you so much for this invaluable fix, Shawn. You've saved my sanity!

The problem I had was that, after upgrading to W10 from W7 this week, my monitor screen refresh rate offered just a single option of 60Hz whereas in W7, I had the option of several higher refresh rates and used 85Hz. This is important for me because I still use a CRT screen and 60Hz gives flicker - not so at the current 85Hz. Sorted. Two days of trying everything I knew, and countless advice from others (including Intel's tech support), and your remedy has finally sorted the problem. Brilliant.

Once again, many thanks.

Unfortunately the fix was shortlived. When I turned the PC back on this evening, the screen display refresh rate has returned to 60Hz with no other refresh rate options - so, back to square one.

I carried out the cache clear and reset again, but this time there was no change after restarting the PC - still just the 60Hz option offered?!? Interestingly, the display driver version reference shown in the Intel HD control panel is consistent but inexplicably (and bizzarely), the display driver ref. stated in Windows settings keeps switching between the one stated in the Intel HD control panel and a much earlier driver version. I'm not even doing anything with the PC at this time, just checking the display driver version every few minutes and it keeps changing. Weird. Can't believe this is happening.

Any ideas/suggestions for a fix much appreciated. Thanks.

Oops! I was wrong about the display driver version number shown in Windows settings. Without realising, I occasionally looked at the Generic PnP monitor driver instead, by mistake. The 60Hz screen refresh problem remains. I suspect the issue has something to do with Windows getting info. (where from?) for the wrong screen. Anyway, thanks for your help so far but I need to shelve this problem for a later time as a more pressing PC backup issue has arisen - I'll post a thread on it.

For the sake of completeness, thought I'd update this thread in case it's useful to anyone else...

I think my screen refresh rate problem is sorted (fingers crossed).

Since my last post to this thread in January 2020, the screen refresh rate on my old CRT monitor has been switching, apparently randomly, between the rate I want (85p Hz) and the lower 60p Hz which gives unpleasant screen flicker on static images. I've done nothing during this time to affect screen refresh rate, nor can I detect a pattern or fathom a reason for the constantly changing screen refresh rate. The screen refresh rate sometimes changes when the PC has been powered up for a while, sometimes it happens at startup. At a guess, I'd say 80% of the time it's set to 60Hz.

Yesterday, I went for broke and disabled the' Generic PnP monitor driver' in 'Device Manager'. I've used the PC heavily since yesterday, turned it off/on a few times and so far, disabling the generic Microsoft driver (dated: 21/06/2006, version: 10.0.18362.693) has done the trick. Now, it could be that a combination of fixes has solved this problem because I still have the W10 registry altered from previous attempts at a fix (see Shawn's tutorial above).

Whilst I still don't understand why the switching between the two refresh rates was so random or how come I've still got a screen display when I've disabled the monitor driver, I'm just grateful to tick off one problem in my long list of W10 issues. (I hope this isn't a case of 'famous last words').

Thanks again for your help, Shawn.