How to reset

Which operating system ??..

HP Pavilion Recovery Partition
Accessing the recovery partition on your HP Pavilion laptop allows you to restore your computer to speed it up, eliminate a virus or repair your Windows operating system.
The Recovery Manager program makes it possible to restore your laptop to its settings as of a previous date or restore your computer to its original factory settings, which will erase all of your installed programs and personal data.
Using the recovery partition allows you to bypass the hassle of keeping track of recovery discs, which could be damaged in storage, rendering them useless when you need them.

Turn on or restart your HP Pavilion laptop.
Press "F11" when the "Press <F11> for recovery" message appears during the HP Pavilion boot process.
Select "Recovery Manager" from your list of recovery options and press "Enter."
The Recovery Manger program will open on your screen, and you can begin the recovery process.
Access Recovery Manager Within Windows
Click the "Start" icon or "Start" button in the lower left corner of your Windows home screen.
Click "All Programs" and then "Recovery Manager."
Click "Recovery Manager" again to open the Recovery Manager program on your HP Pavilion laptop.
using the hp recovery manager in windows 7
or
While restarting the computer keep tapping on the F10 key
on the next screen you will find start system recovery , and on the next screen you will find advanced options
in advanced option you will find an option for Destructive Recovery.. click that

If you are not able to run the recovery on the computer as above then you will need no use a set of recovery cds..... if you dont have them you can get it from HP..
or
HP Desktop factory settings
The HP Recovery Partition that comes pre-installed on most new HPs is like built-in insurance if your system becomes unstable or fails.
If the problem is severe enough, you may not be able to start the HP Desktop Recovery Manager from Windows but you can start it manually by following the steps below.

Disconnect all peripheral devices and power on the computer.
Press the F11 key after the computer first powers on to start the HP Recovery Manager.

Follow the on-screen instructions to back up recoverable files on the hard drive to an external drive or media.
Continue following the instructions to recover the hard drive to its original factory condition.
Click "Finish" when the recovery is complete.
Reconnect devices and reboot the computer.
Reinstall software and update Windows and HP to current settings.


Performing an HP System Recovery (Windows Vista)