Windows 7 - Keyboard Problem (Ctrl and Shift keys don't work correctly)

Hello everyone. Today my shift and ctrl keys stopped working correctly... it happened while I was playing and later when I tried to change the language using Alt + Shift. I checked if Sticky Keys and other similar options weren't turned on by accident, but they weren't.

And after some time spent in trying to fix the problem I opened the On-Screen Keyboard and noticed that when I use my Ctrl key, Shift is pressed automatically as well (it's just what On-Screen Keyboard says). The same thing happens when I press Shift, then the Ctrl key "presses itself". It so happens that all four (left and right shift, and left and right ctrl) keys are pressed at the same time, when I press just one of them.

Does everyone know where the problem could be from and how I can fix it... it's really annoying, I can't use any of the combinations like Ctrl + V, Ctrl + C, Ctrl + A, etc. The problem started while I was playing Assassin's Creed; I sometimes hear sounds like too-much-buttons-pressed while I play it, but I've never had this problem until today. I have no idea what it could be, I tried everything I know.

If it helps, the problem is still there while I chat or surf the web through Asus Express Gate, when the windows isn't running at all.

PS: Sorry if I used strange phrases or words, I am not a native English speaker.

See if pressing both 'shift' keys at the same time, gets your keyboard operating correctly again.

Nope, I read it somewhere and I tried it... still, when I press both shift keys, the ctrl keys press themselves. I can't press ONLY the shift keys together.

Have you also tried pressing the shift key 5 times in a row or holding it down for about 8 seconds?

hello and welcome

now is the keyboard usb connected or ps2 connected? have you checked all the settings in keyboard settings to how you require them ? go to device manager and uninstall the keyboard driver pull the connection (usb or ps2) now reboot as machine is rebooting put the connection back in and wait for windows to install the drivers (make sure you are connected to the web in case windows need to access the internet for drivers) .
also have a look here for any help with common windows problems Microsoft fix it center>>
Microsoft Fix it Solution Center

That would be the Sticky Keys' shortcut? It was working until today... now when I press Shift five times or hold it down for 8 seconds, it is like pressing/holding Ctrl key as well, and no shortcut appears.

@brianzion
The keyboard is PS/2 connected, and I have also tried re-installing the drivers, Solution Center wouldn't find a problem, it isn't an actual problem for the system, it is a problem for me. Windows wouldn't mind if Ctrl is stuck to Shift.

Is there a way to check if it is a hardware problem apart from trying another keyboard (which I am looking forward to; I'll try it as soon as I get the chance).

tried this
Right Shift for eight seconds to Turn Filter Keys on and off ????

does this help??

No, if I press Shift, Ctrl key is pressed and for that reason no shortcuts work. I tried all those options -- Sticky Keys, Filter keys, Mouse Keys, etc. -- but nothing fixed my problem. If there's a particular option in some of the Keys options that can somehow "lock" a key to another so that every time you press one of them, the others are pressed as well, it could be the solution.

I don't know how Express Gate works and if it's connected to the windows, but if it doesn't use windows drivers, the problem should be the keyboard itself.

yes you may have to change the keyboard at least try a new one to see if that solves it if you use the keys for gaming( pressing the keys fast and hard) im sure the little boards underneath inside wont last long.