laptop keyborad

I am using a toshiba satelite laptop. and win xp sp2. and office 2003 prof. for last few days when i type spmething and wait for a while, then suddenly everything copy automatically and paste also automatically. few say it is avirus proble, few say yboard is short etc. now when i type if i press suppos ‘f’, then it happens fffffffffffff, or if i type ‘mass’ it type after few sec, mass mass mass mass…… like this. what I do?