Why don't the arrow keys on my computer work properly?

My laptop, toshiba, microsoft 7 (the one where microsoft word’s tabs are all laid across on the top), is not working right. Whenever I use the arrow keys, especially in flash players, they always tend to get “held down”. Example is when I press the arrow key once, it will keep going that way and won’t stop until I type that same key again. Anyone else have this problem or is it specifically my computer? It has been going on from (literally) the first day I bought it.