HP Recovery Center
Be advised that this will take the machine back to the point when you first took it of the box.
The "HP Recovery Center" will give you the option to send to backup anything you
don't want to lose, so have backup media available to use if you choose this option.
With the machine off press the power button, as soon as you do that start tapping the F11 key.
It may take several attempts to do this, if the first attempt fails, try again.
That should take you to the HP Recovery Center. When there just follow the prompts.
It is pretty much self explanatory. From the time you boot into F11 (not counting
any backups you choose to make) you should be back on a working desktop in about
30 minutes. After it restarts just follow the prompts again to finish the process.
If your first option is system restore select no, which should take you to system recovery.
You want to try system recovery not system restore, unless you have good restore points!
If you don't have a Vista install disc and you want to do a "Factory Recovery" you
can contact HP with the model number / serial number of the machine in question
and they will send you a set of recovery discs for your machine for a small fee.
HP keeps copies of recovery discs for almost all the machines they produce.
You need to check HP's site to see if there is a hidden restore partition on that machine...
The instructions for doing a restore vary from manuf. to manuf....
Also if you have the Vista product key you can simply borrow a Vista CD as long as the versions match...
This is perfectly legal.