Now a days the worst problems is hanging of computer or laptop when u do an important work or chat online.This problem of hang or freeze is due to some virus and malwares.
If your pc hangs firstly check whether your cpu fans are working properly.Secondly check that too many applications running at anyone time.If fans are not working properly then replace it with new one and Close un wanted application from running at a time by pressing ctrl+alt+delete and click the unwanted application and click at ‘END TASK’.
1) If the above are well and then use Power Defrag and Smart Defrag from download.com.This 2 softwares fragment your pc to process fast and with out hangs.
2) Use Spybot Search and Destroy ,Avira AntiVir Personal Free Antivirus and AVG Anti Virus Free Edition for antivirus check and spyware check
3) Remove un wanted videos,music,softwares etc
4) Restart Your Pc and start your work
5) If Again it Hangs then in my view you should format your hard disk and install your operating system that may be xp 2,xp 3 or vista.I recommand to you to use Xp 2 as your operating system because it is best operating than vista and others..
If there is same problem then i think that there is problem in your hard disk and go to near by computer repair shop and tell your problem and ask him to check your hard dish.If there is problem then ask him to make it right and if he unable then you should purchase a new hard disk.