Acer aspire 4520 hardware problems

You'll want to go to acer's support site, find your model, and download the appropriate Vista drivers.

Did you buy the laptop retail or online? If you opted to get some recovery CD's with it, you may want to use that to re-format the laptop, otherwise you may need to get into touch with Acer about ordering one, or possibly going for a copy of Win 7 and formatting it using that instead.

The first thing you need to get done is backing up your data before you take any action.

Aside from that, what anti-virus are you running? Are you sure you don't have a virus thats messing with you?

How old is your laptop? If its a Vista system with 1gb (inadequate by Vista/Win7 Standards) I'm gonna go ahead and assume its from the year 2006 or somewhere around there. If that's the case, your laptop may be on its way out. 2-3 years is all I'd expect out of a laptop. So maybe it might be time to explore some options concerning jumping ship to another laptop entirely.