if it's not dirt Donna, the only other thing i can think of is that the circuitry is slowly detaching.... you mentioned earlier there was a pattern...

i'd recommend taking it to a repair shop at this point - but don't leave it there. ask:

1. how much it will cost JUST to open it up and diagnose the problem?

2. what might be the range of repair cost, based on possible problems?

some repairs - especially to laptops - are just not worth it, but it depends on what is wrong. it might be cheaper to buy another one.

how old is your laptop anyway?