What is your OS?
What is the Ram?
What the hard drive you have and what kinds of software you have downloaded, Do you have anti-virus a d internet security ?

What type of laptop you using and the specs?  If you give these infos along with your problem someone might be able to pinpoint the problem and give you right suggestion otherwise you may get funny comments ( overlook them).

Virus , not enough ram to run programs, overheat will make your computer freeze.
( Are you a DV winner? )