my pc hangs up after opening some application,leaving it for some time that is approximately 30-1hour.the application may be movie ,songs etc....

Is the application Windows Media Player or ... ?

Note the time of one of these hangs & then:

Look in your Event viewer: rt. click My Computer then click Manage then Event Viewer.
Or: Administrative Tools/Event Viewer or Start/Run/ eventvwr
Open the system as well as the application tabs & look for X errors. Click error line for details.
Post back the source & event id especially of errors that seem to coincide with a hang.

Iam not getting that kind of errors.It does hang up for all applications,running it for atleat 30minutes to 1 hour.it has nothig to do with the windows media player.pls guide me in proper way

Just to clarify:

Your PC freezes after it is on for a ½ hour to an hour? It freezes & you have to power off manually?
Can you turn it back on right away? Are the fans working?
Is this a new problem?
Sounds like a heat issue or bad RAM.

You have absolutly NO errors in the Event Viewer?
Did you Open the folders?

You can try to run a Check Disk:
start > run > cmd
in the new window type chkdsk/f
when prompted to run on boot choose Y & reboot
this will check for & fix any disk errors.

Also: go to start/search/ (type in): .dmp
Do you get any finds?

If so then:

1) Download and install the
Debugging Tools from Microsoft
2) Download and install this
debugwiz
3) Open the Wiz & Browse to, or paste in the path to, your latest .dmp file.
4) After the Wiz creates a Text document post it back to this thread.

i resolved the issue myself.what i did was,reinstalled the xp windows. i guess i do have some hard disk errors but when i gave disk checking option to windows i think it is working fine .one thing is certain,when i start my computer after half on hour my pc getting heated up u think it happens after half an hour? i also noticed my hard disk dissipated heat,when i touched.i really dont know what the issue.u expert can solve my pc problem
if u could resolve u get million dollars....................just kidding
the place where the pc is placed is having lot of heat do u think it is due to that?

If you resolved the issue by reinstalling XP then fine.

If your machine keeps shutting down then I would suspect Heat first.

You can get some monitors with this program

http://www.lavalys.com/products/over...ng=en&pageid=1

Look under: Computer | Sensor

If it continues to crash explore your Event Viewer & or get your .dmp logs as described above for further analysis.