Here are few of things that you can do to reduce the problem from happening:
1) put your computer into "standby" or shut it down whenever you don't neet it, this will let it cool down.
2) download Ad-aware from
http://www.download.com/3000-2144-10045910.html?part=69274&subj=dlpage&tag=button
run the software once a week to get ride of most of the spywares (pop-up ads, etc.), remember to check for update each time before you run it to get the latest definations.
3) if this still not help, run the recovery CD that comes with your laptap (not recommended if you are not very good at computers). This is a big opration, be sure all your important files are backuped before you do it, because everything will be erased by doing so.