I believe some are protected. Right click on the key you want to remove and look at permissions.
I have tried deleting some register keyS on my computer. A pop-up message said that it was unable to delete the key; that it was locked or something. This was tried in the Normal, Normal with all programs closed/disabled, and Safe modes. Each time I tried to remove or delete a certain register key, I was denied.
Is there any way that I can render the keys in the register to a state where it can be deleted? Am running Win 2000 Pro. Appreciate any assistance you may offer.