keyboard and mouse stop working at login screen

I'm on win 7 pro with all updates. 100% sure that I didn't install any software or change any setting but just restarted my computer because it felt slow and its been a while. I do this every now and then to get good feels. Problem now is at the login screen, my keyboard and mouse don't work anymore. The same problem happens even when I select safe mode. I must mention that I've been having monitor problems in the last 2-3 days but I can't see that connected with this issue. Or is it? My dell ultrasharp is dying it looks like. Half of the screen to the left is flickering and the rest half is alright. After an hour or two it looks fine but then the problem comes back. I'm gonna buy a new monitor but this login issue cannot be connected with my monitor going bad right? The monitor is exhibiting this issue in the POST and BIOS screens too so I'm guessing it has nothing to do with the video drivers.

Any tips would be greatly appreciated. Thanks.

I must add that the keyboard/mouse works during the POST and BIOS setup screens. I'm also able to select safe mode option after pressing f8 in the advanced boot options

I would recommend fixing the problem you know you have first. Whether it will fix the keyboard/mouse problem or not. Replace the monitor with a known good monitor for testing.

The next thing to do is help us help you. We need your spec filled in completely.

These two tutorials should help you in that task.

Br Brink:
System Info - See Your System Specs

By Kari:
Speccy - Publish Snapshot of your System Specs

Layback Bear said:

I would recommend fixing the problem you know you have first. Whether it will fix the keyboard/mouse problem or not. Replace the monitor with a known good monitor for testing.

The next thing to do is help us help you. We need your spec filled in completely.

These two tutorials should help you in that task.

Br Brink:
System Info - See Your System Specs

By Kari:
Speccy - Publish Snapshot of your System Specs

Thanks for your reply.

I got a new monitor and the display is running without problems. I'm unable to install the software you recommended because I haven't been able to get past the login screen because of the keyboard and mouse not functioning as described earlier.

I booted into the advanced options F8 and tried the following :
1. Booted into safe mode. Login screen shows but keyboard and mouse don't work.
2. Used last known good configuration option. Again reached login screen but keyboard and mouse don't work.
3. Chose repair computer option and clicked startup repair and tried again. System rebooted and again same problem. Here keyboard and mouse worked
4. Ran Windows Memory Diagnostic. No problems. Ran successfully.
4. Just did a system restore to a point just before a critical update was applied via ms update 24 hours earlier and booted to the login. Still no luck. Keyboard and mouse don't work.

Keyboard is working fine during POST and in BIOS setup screens.

Connected the keyboard and mouse to different USB ports but still no luck.

They are surely working fine because they are working fine in the repair my computer options screen.

I also connected my mouse and keyboard to my macbook air and they are working fine. The keyboard letters lights up when its active. Mouse's laser also lights up when its working. Both lights work when connected to my macbook air.

Anybody know what I can do? I vividly remember not installing any software or making any system related change in the computer before restarting.

Can you use a PS2 mouse and keyboard so you can get into Windows and do some testing?

How long have you been using Ultimate and where did you get it from?