I am programming a game in microsoft visual studio c# and I have to catch lot\'s of keys simultaneously. I can\'t detect Q,W,E,R,T,Y at the same time but I can detect Q,W,E,
This is known as key rollover. USB keyboards only support a finite key rollover, whereas some cleverly-designed PS/2 keyboards have n-key rollover (many many keys may be depressed at the same time without muting additional keypresses)
Have a read: Wikipedia Description
It may be related to your keyboard. When I was a gamer, I know that it was a property of keyboards to be able to send multiple keystrokes at the same time; Depending on the keyboard, the number would differ, but also the different combinations would or wouldn't work.