Hello, I have encountered a rather odd problem that didn't turn up in forum search.
System: Windows 7 Home Premium 32-bit, fresh install+updates (with AVG 2012 Free and Google Chrome as only other installs)
I have (had) 2 users both with admin rights. One was my 'main' user that I was using just to learn Windows 7 and surf a l'il. The other was completely new: Created, logged into, back off, then not touched again. For the first few days, had no problems and was really liking Windows 7. However, today after logging off main user (I had just run a full clean scan with AVG, btw) and switching to the fresh one, IMMEDIATELY after entering my log-in password, I received a UAC prompt telling me that this user does not have access to this folder. The background was replaced with a black screen, the taskbar icons were replaced with the standard "new file" icon and did not function (no surprise there.) I opened Windows Explorer using "Start > Computer" and again was immediately told I had no access. Gave myself permission and attempted to investigate. I could not view/open any folder without giving myself permission first.
Having no success determining the problem, I decided to simply log off and delete this account. Performed a full delete (folders and all.) Then, I created a new account with admin rights. Logged into it without incident. Logged back onto main user and opened Windows Explorer. The user folder from the original 2nd account remained and I was denied when trying to delete. Probing into it, I found a Windows Media Player database file under User\AppData\Local\Microsoft\Media Player. I was told this file was in use by another program and I could not delete it. I did not have any programs other than Explorer running on any user at the time.
I remembered that I had tried to open a stock music file in Explorer under the main account earlier. WMP had opened and started its "First Use" spiel. I had chosen custom settings, then I believe that I had closed WMP after the file extension association dialog opened without confirming the associations as I did not want to use WMP for anything. At this point, I had continued doing other things without problem.
Eventually, when I switched users this whole mess started. Remembering the WMP stuff, I again opened a stock music file (still on main account.) WMP ran its setup routine again and I allowed it to associate and run. I closed WMP, browsed to the old user folder in Explorer and deleted it without problem.
I have tried, unsuccessfully, to replicate this event by creating 2 new test users and shortcutting the WMP "First Use" setup again on each of them. So, I cannot be certain that this is what caused my problem, nor that it will not happen again. Any ideas?
Deeply Appreciative, Win7BlankUser.