Keyboard problems. Ongoing keys plus nonworking keys.

Hello,
When I type on my computer, a dell latitude, some keys will type on for ages
Ect. Wwwwwwwww
Or if I hit a key completely different that W will show up and keep going.
A lot of keys will also tend to not work.
It's different keys each startup and I don't know how to fix it.
Help?