Getting a bit confused after cpu upgrade

I wonder if someone might point me in the right direction please. I have just upgraded my cpu (no other changes to my system) and I am getting the 'significant changes have been made' error when I launch DCS. I have followed the instructions to activate my modules in these dialogue boxes, and the game eventually launches. In module manager, all my modules show up, but when I try to run a quick mission to test, I get sent to the map view, with no way of flying the chosen aircraft.

The T-51 works ok, so I am guessing it is something to do with activation, but the error messages are saying that activation has been successful, and when I click on the 'installed' tab in module manage, the buttons show up green as if they are correct.

I have only found out about the notion of deactivating modules after I have run into problems, I wasn't aware of that so I didn't do anything to DCS before doing the cpu swap.

Just a bit of advice as to how to get up and running again would be appreciated, thanks in advance.

edit: I've been through the steps in the technical support section, short of manually editing the registry. I thought I would post here first before doing a step like that.

edit edit: It's the older modules causing the problem, the Spitfire, Harrier, F-18 are all ok.

^ That's because Spit, Harrier and Hornet already use the new, keyless DRM system, while most of the others will be converted later.

Nothing wrong with purging the registry entries, I did it myself a couple of times (you mean the guidelines posted here I presume? https://www.digitalcombatsimulator.com/en/support/faq/564/#1780273)

Thanks for the nudge in the right direction Art, after a bit more faffing with registry entries I think I am back up and running now. Editing the registry to get a computer game working, mmm. Anyway I'm going to drive the Ford Escort down to Blockbuster and get a vhs movie tonight. That new one with Tom Cruise about the jet planes looks good

Thanks again for the advice