I faced this issue on windows 7 home edition where the user was not able to press any key from keyboard more than once. If the user has pressed the “a” and like to press again he/she has to press some other key and then he/she will be able to press the “a” again.
There is a functionality in windows 7 that if you press the shift or any other key more than once in a very short time. It gives you option to stop this to prevent some damage to the system.
It can enable the “Turn on Filter Keys” in windows 7 which leads to the above issue. To solve this issue please follow the simple steps given below.
Go to Start Menu of Windows 7
Enter “Ease of Access” in the search bar and press enter
Ease of Access center will be opened.