There is another option too. If you're more interested in just getting ahold of the hp g72 restore disk you can just order it from the manufacturer.
If the manufacturer doesnt carry the disc then you can also choose to purhcase it from a third party. We end up having to get our discs from third parties in certain situations, like if the customer doesnt have the disc, or the manufacturer did not provide the disc with the computer. A lot of the time customers might misplace the discs too. In these situations we go to recovery-disks.com or another third party to order the discs.
That is the link for your computer. Use that to place an order and get your disc set. This will allow you to FACTORY RESTORE back to the way it was when you bought it.
When you get the discs, or you use the ones that you have already, follow the directions that came with them. They are really easy to install. Often times we just tell the customer to order them for their computer and install the CD's themselves. Saves them some money!