Unless your comfortable with taking apart your laptop, take it to a shop for this, but I would suggest taking it apart and cleaning out underneat the keys. It's probably got a bunch of crap under there. Also, your mouse freezing could be due to viruses and/or a bunch of programs using up your system's resources that you don't need. I would suggest going start > control pannel > add/remove programs. From there uninstall any programs you dont need/use other than the ones that say "Microsoft" in the beginning.

As for virus removal, I would suggest Malware Bytes Anti-Malware. It's free and works really good.

If you want to know how to Fix PC and make your computer run faster, I think this tools would help you: http://spotmau-powersuite.kooksoft.com/

You can use it to boot up any computer; fix and install Windows; optimize and speed up your system; clean up history and protect privacy; recover data and passwords; partition and format the hard drive; clone and backup your system; and more...

if you have any questions, you can use http://answers.yahoo.com/ for more answers, hope my answer is useful for you, good luck.