Laptop start-up problems

Hello,

Last week when my dad logged in, he found a new desktop screen and none of his files. My dad's laptop is password protected, so he thought it may have been that another user was created on his laptop without him knowing. We tried logging in with his password many times. But the result was the same. Gateway desktop screen with several programme icons, but no files. His name was still on the Start Menu. But when we clicked it, we found only an Atheros file and nothing else.

The next day, before we could take his laptop to the IT guy, it worked properly. My dad got his desktop screen back with all his files intact. So we thought nothing of it.

Yesterday, I tried to log in on his laptop, but I got a message box saying that Windows has found a start-up problem and was trying to repair it. It didn't work and I couldn't log in at all. After several hours, I logged in again, this time there was absolutely no problem.

I don't know if the problem is with the software or hardware. So I don't know if I should take my laptop to Gateway's support center or I should get in touch with Windows.

Can someone please help?

Nawee