UAC message don't show up and other random problems with Windows

I didn't get any replies in another (old) thread, so I thought I'd make a new one.

My main problem is UAC prompts don't show up. When I open an admin program, nothing happens (the mouse implies it's loading, but nothing happens). When I start an admin program from a non-admin cmd (because I can't open an admin cmd), cmd just hangs. The win+R window just disappears and nothing happens. The start menu closes, but is then unusable when I open it again, because it's still trying to start the program. UAC is at it's maximum setting.

I tried starting Windows in safe mode and the affected programs just run there, because there's no UAC in safe mode.

Also, MS Security Essentials's real-time av is disabled and I can't enable it (because I need admin rights for that).

I also did a system restore to a couple of days ago. After the system restore finished and Windows had rebooted, Everything worked fine. But after shutting down and booting later on the day, the same problem occurred. I've tried restoring to two restore points, both with this effect.

Some more things I found out.

The wifi icon in the taskbar doesn't do anything. It just sits there in it's "connecting mode" (empty bars plus a loading circle) and clicking it has no effect whatsoever, i.e. no popup with current connections and wifi APs. This is regardless of whether the wifi adapter is enabled or disabled. (I can toggle that with a hardware button on the laptop, network center doesn't work.) When the adapter is enabled and I'm near an AP I've connected to before, I can browse the internet using Chrome.

The first time I had the UAC problem, Explorer didn't work, probably because the RPC service wasn't running. Error message I got: "The remote procedure call failed and did not execute". I couldn't check the RPC service, because you need admin rights to open services.msc. When I say Explorer didn't work, that means it only didn't work when I wanted to open a window. Taskbar did work. After a reboot this problem was gone.

I did a full scan with MalwareBytes and Microsoft Security Essentials (in safe mode), both didn't detect anything.

I just tried to start in normal mode. After I logged in, I got a black screen with a little message box saying "Please wait". Never seen anything like that message box in Windows before. Then, nothing happened. It turned out the black screen actually was my desktop, but Explorer didn't start and the background didn't work. I then checked task manager (ctrl+alt+del just worked) and found that only very few processes were running (about 15).

Another scan I did came up blank. This time McAfee's Stinger, also in safe mode.

A day later I started in normal mode and everything just worked fine (as if I had just done system recovery, like I mentioned earlier). I did full scans with MalwareBytes and Microsoft Security Essentials and both again didn't detect anything. But after restarting, everything was back to bad again (again just as if I had done system recovery, though I really didn't do that).

Anyone got any ideas on how to fix this? If you need more details, feel free to ask.
Would it be a good idea to try and turn off UAC through safe mode to get admin rights in normal mode? I'm hesitant to do this, because malware might also get more access when I do this.

Solution by dusters16: (don't forget to add to his reputation)

dusters16 said:

1. Turn off computer buy holding the power button.
2. Turn back on, tap F8 until you get the Safe Mode menu.
3. Boot up in any of the Safe Modes
4. Once in, go to Start > Control Panel > User Accounts
5. At the main window, there is an option for Change User Account Control settings.
6. Drop it to the bottom and OK it.
7. Restart and let it boot normally into Windows.
8. Once in, go to the Programs and Features
9. Find Microsoft Security Essentials and Uninstall it. It might take a while (like over 10 minutes or more)
10. Restart once it finishes.
11. Turn on UAC, restart.
12. Make sure everything works
13. go gran another AV temporarily

I am working on finding out which Update causes this. This has affected clean installs of Windows with all Updates and no other 3rd party applications installed.

dusters16 said:

I have the same problem in about 4 computers so far. Simple fix is to reboot to Safe Mode, turn off UAC, reboot normally, uninstall MSE, and turn UAC back on, then reboot.

I am still figuring out what Update is causing it.
After seeing these computers like this I am installing MSE after ALL the Windows Updates have completed. So far so good.
Be wary though that after you are affected by the original issue, uninstalling and reinstalling MSE does not permanently fix the issue. The computer might be ok for a few reboots but the problem will come back. Try using another free AV for now (but not AVG, I have seen it break Windows to many times).

hey thank you for registering and posting this, I've had this issue for a few days now.
It's a tad worse thou, since following the instructions don't fully work.

reboot to Safe Mode, turn off UAC, reboot normally,
I am not able to uninstall MSE, the computer is completely locked up so whilst I can actually click uninstall, it just sits there forever. and trying to do the manually uninstall route dont work;
How to manually uninstall Microsoft Security Essentials 2.0.1963 if you cannot uninstall it by using the Add or Remove Programs item
sc config msmpsvc start= disabled
into an "run as administrator elevated CMD still responds as access denied. in normal boot and in Safe Mode.If I try to update windows I just get an unresponsive empty window etc, so I never get to even try to uninstall. and turn back UAC.
Thing is its not that the %&/&& computer even "wakes back up" after 10-15 minutes, it takes many Hours. It woke up back into a usable state one time today and that is after using it all day in lectures. (University student)Seems to happen when I get completely frustrated and stressing the computer multiple explorer.exe force close / restart rapidly etc. (even thou the wifi icon is locked up it does connect to the network in the background, trying to connect to network samba servers(network resources) rapidly, seems to sometimes push it out of its locked up state.)

But having read your post I'll remember to uninstall Microsofts antivirus the first chanse I get.
(it's a almost untouched computer new this semester so not full of crud etc. and most computers on the network it connects to are linux, not much chanse for malware. etc.)
This is driving me very angry since I'm forced to work with the computer for hours every day even in this semi-working state. I'm close to giving up and installing FreeBSD or Debian on this thing but dont really wanna mess with my laptop as I do with desktops.as its only for serious work.

EDIT: uninstalled microsoft antivirus once I got a chanse the UAC lock released, took a few hours of casual use but its now solved, thanks again dusters16!