Laptop keyboard acting strange

Hello,
I am using a Toshiba laptop with VISTA and every once in a while my keyboard acts strange. Each time I hit the same key a different character appears on screen - and it scrolls through the entire keyboard. For example, if I hit the "S" key 8 times in a row I get q,w,e,r,t,y,u,i, etc. I get the same result with every key.

It happens in WORD, POWERPOINT and EXCEL but not in email. It also happens frequently when I close the laptop to put it to sleep and then try to logon. My password will not work because the keyboard is not working properly.

Does anyone know why this is happening or how to fix it? Thanks for your help.