I purchased a computer several years ago. Windows 7 was pre installed. I've several crashes and I've had to rely on a computer repair shop to fix the problem. They have always had to reinstall Windows 7 again. I believe that I could have solved my own problem if I had had a disk. Can Dell supply me with a Windows 7 pro disk. If not and if purchase the program localy, will it reconize all the drivers and other information on my computer.
Backup all necessary data from My Documents, Pictures, Backups for individual programs that you need etc
Ensure you have a copy of all necessary drivers (download them from the official HP site for your pc and backup to dvd-r disc).
Have a second pc to use if things go wrong and you need more information
Format the HDD using Active Killdisk or similar utility. This will format the HDD at a low level and ensure all viruses are removed (unless they escaped on your backups, be careful).
Reinstall Windows from an OEM copy of Windows which is the cheapest option and will give you a license key. These can be obtained from Ebay very cheaply. Remember that if you hardware changes then this copy may stop working but on the same computer it will be fine.
Reinstall drivers and restore backups
Your computer is working again! No need to give repair shops any money at all.