Windows 7 Behaving as if Alt Key is Stuck

[upto]

I have a Lenovo G570, running Windows 7 Home Premium 64-bit.

I first discovered this problem a few weeks ago whilst playing Heroes Of Newerth, it was behaving like ALT was being held down, I couldn't type and it was unplayable, it happened many times and it seemed to only happen during or after I had played HoN. But it gradually became worse and started happening all the time and when I hadn't been playing at all. I clean re-installed Windows 7 Home Premium twice since then and it has gotten to the point of me being unable to type to login upon restarting the computer.

It seems to stop temporarily (for only a couple of minutes) after time but doesn't stay corrected for long. When it does happen I can't type, and when I do push keys it goes to the shortcut associated with the key as if I was holding ALT (e.g pushing F brings up FIND/SEARCH) and double clicking a folder brings up the folder's Properties menu.

Thanks to anyone who can help, I searched everywhere and couldn't find a solution anywhere.

Also I have taken my laptop apart as well as plugged in an external keyboard and have determined ALT is NOT being physically held down/stuck.

 

[bassfisher6522]

The key may not be physically stuck, but with laptops the pressure point that is underneath the key that receives the signal may be damaged. You may have to take to a Lenovo service dealer/repair center or at least a certified lenovo repair center. Is it still under warranty?

 

[TrainableMan]

I suggest you download and install KeyTweak and use it to remap your Alt key and see if your issue stops, if so then it is the keyboard.

 

[Digerati]

Also, make sure you are not accidentally enabling "Sticky Keys".