I have Desktop Comp. when i logged in Guest account my pc works fine and my internet connection also works good.
but when i logged in Using Admin account my pc suddenly slows down and internet connection also not work properly, continuously i refresh my connection.
i m not getting what happened, i format n reinstall windows but my problem didn't got solved.
Thanks in advance.

This problem happens to Vista also. Are you using Windows Xp? How many mb of data does the admin account and guest account have? Does this problem happens when you are in safe mode?

ya i m using XP. Admin account doesn't have large data,
i recently format my PC hence didn't install much software.
just VS is installed.
this happens in normal mode.
but when i tried in safe mode same problem occurred.

When you tried in safe mode, can you log it using admin account? What is the amount od data on your guest account?And on your admin account.

i logged using admin account, and i have hardly 30 GB data on overall.

Try to create another account (another user set with admin) and try to log in to the newly created user account.

If it slow down as admin account does, perhaps you might need chkdsk your windows directory...

ya in another new admin it works fine. bt not in my admin. i will try chkdsk utility.

And also check using msconfig and event viewer for startup programs, possible errors and service loading errors.

Use the new admin account and delete the old admin account. Backup your data on an external hard disk first. Since nothing is wrong with your second admin account you might as well you that. Follow the two above posted suggestion first.

So did it work. Does the new account has any problems and what happen to the old admin account?