If you believe your user account is corrupted, you will need to copy the files from the corrupt user account to the working one. You need to be running as an adminstrator to create a new adminstrator account. You should also create a Limited User Account, which is the account you should transfer all of your data to. You should only use the administrator account to make major changes and diagnose problems.
To create a new account in Windows XP (Administrator or Limited User):
1. left-click the start button, and left-click ‘Control Panel’.
2. double left-click the ‘User Accounts’, and left-click ‘create a new user account’
3. Create a name for the user account and choose whether you want it to be an Administrator or Limited User account.
4. Proceed to copy your files to your new user account. Once the files have been copied over, proceed to delete the old corrupted user account.