Wrong letters appear when I type, window goes crazy and closes

i'm running windows 7. when i open the window at first its find but after a couple minutes of being on when i type the only thing that comes up is /n after a little longer if i hit the space bar the window will minimize.after the window goes crazy the window will just close up.i tried reinstalling 7 but the same thing ran a scan to check for virus came up clean. if someone can help it will be appreciated

Take a look in Device Manager and select Keyboard. See what it says under the Hardware tab next to Device Status, normally it would say "The Device is Working Properly" which yours clearly isn't.

Do you have, or can you borrow another keyboard to try out?

thanks mark, i finally fixed it. i added more ram and when i put the keyboard back in i put it in to tight. thanks for help

Well done, and your welcome.