Good to hear, that's a start. At least we now know the issue is account specific. Run CCleaner again on main account, both the registry cleaner & the first tab. I wonder if something is amiss ... perhaps remnants of your old security package or something else that is blocking. Trying to find the problem could be extremely difficult. It might even be a hidden file .. a preference file of some description. I'm not a windows wiz on finding such things.

On mac I can run multiple accounts at same time. lol I discovered you can also do that with windows & have two LW's running simultaneously, but that's obviously not the answer we are looking for.