Before you go any further, it is highly recommended that you take a backup of your existing system using a bit-level disk cloning utility, such as one of the following (listed in no particular order of preference).
- HDD Raw Copy Tool by HDDGURU (Freeware)
- PING (Partimage Is Not Ghost) by Effitek (Freeware)
- Paragon Backup & Recovery by Paragon Software Group (Free Edition)
- Acronis True Image WD Edition Software by Acronis (Free, target drive must be Western Digital)
- Seagate DiscWizard by Seagate (Free, target drive must be Seagate)
This will allow you to roll back to Windows XP if the upgrade doesn’t go as expected.
You can also use these utilities to migrate your existing system to new hardware as part of the upgrade if you wish. Perform the upgrade process as instructed in this post on the existing hardware. Once you have completed the Windows 7 upgrade and patching, take a backup of the system and clone the disk(s) to the new hardware.