I have two problems which I am not sure if they are related.
1st - some time ago (a year or more) I changed the permissions on my folders to allow permissions for everyone. I don't remember the exact folder(s) - it was probably documents and settings. I now know this was very bad. I have nested Application Data folders in C:\users\all users\application data. My last count was 27 of them. The storage used on my c drive seems excessive considering my intent is to use it mainly for programs and I store my resource hogs (music and video files) on external hard drives. I encountered quite a debate on whether changing the permission and possible related junction problems actually cause this storage issue - so I don't know. Several people mentioned success with a utility called JunctionBox, but I have not found any recent information on it (the original posts are in 2011).
2nd - windows explorer tends to hang and use up to 50% of my CPU. It does not do this on bootup, but I have noticed it happens after I spend time copying/moving files around. This usage continues even when no other applications are open. I usually have to restart the computer to reset it.
I am using windows 7 64 bit. Malwarebytes detects nothing. I have just finished a backup. I have a system restore point from 2 years ago, but I don't know if I had changed the permissions at that point or not. All other restore points are recent. I also have my windows 7 disks.
At this point I am considering trying the 2-year old restore point. But I am not sure how that will affect other applications (such as iTunes or VLC for example). If that doesn't work - I'm on to the reloading windows itself.
I've probably learned just enough to be dangerous to my computer, so I'm looking for more expert guidance in tackling these issues.