This is a very common problem. The recovery disks that HP provides with their new PCs do not work if you replace a hard drive or remove partitions and format your existing drive. HP has set up their BIOS and hard drives with check keys. This allows them to make sure that you cannot go to the store and buy a hard drive, but instead must call HP and purchase a hard drive directly from them. Alternatively you can purchase the recovery CDs from HP which (they claim) WILL work with a store bought hard drive for and then you must wait for them to ship the CDs to you. It is unfortunate when a company goes out of their to make it difficult to use their products and tries to nickle and dime their customers. I am p***ed that in order to get my under warranty system back up and running I have to spend 1hr on the phone with support and then pay for them to ship the recovery CDs that (they claim) will work with a new hard drive. What a pain. I will recommend that my clients avoid HP computers until HP works out these issues. Dell computers do not have this problem. I do NOT like that a less than one year old computer that is under warranty cannot be rebuilt without extra payments to HP and days of shipping time. Caveat Emptar.