Suddenly, wheever I try to install anything, I get as far as the step where shortcuts are created and the installer informs me it doesn't have permission to continue. It says it can't access the folder where the shortcuts go. Hitting retry repeatedly doesn't change anything, so my only option it to cancel.

R-Clicking and running as administrator doesn't help. Taking ownership of the Users folder and all sub-folders doesn't help either. My Users folder contains various sub-folders, some of which aren't accessible. UAC is disabled.

Since this is a home PC and I'm the only user, is there some way to get rid of most of these accounts (My Users folder has 8 Sub-folders: Administrator, Administrator.Tom-PC, Administrator.Tom-PC.ooo, All Users, Default, Default User, Public, and Tom), and just keep the bare minimum necessary to use my system? I've used Windows since it was first released, and various DOS versions before that, and I've never seen anything as hosed up as this.