It is possible to load win7 pro.
However you'll be unable to use memory over approx 3Gb total.
You may find that tech support if called may not help you with the Windows you install. simply because they are not required to support any windows but the one they sold with the machine. Note that OEM versions such as are installed on a new machine must get support from the computer vendor not Microsoft. Retail versions get support from Microsoft.
You will need to get all the proper drivers from the manufacturers website. Some brands such as Sony or Toshiba require things in the proper order to work properly.
Any bundled software will need to be bought somewhere.
There is no huge difference for the typical home user between Home Premium and Pro versions beyond the fact that Pro sounds more impressive and costs more. If you need the added features in Pro than that is a different thing. I run 64 bit Windows 7 and so far I haven't had any of my old software refuse to run. A couple of things I had to change a option in the program one time and then done.
These seem to be the big differences between them from here. http://windows.microsoft.com/en-US/windows7/products/compare
This one gets into more details. http://www.neowin.net/news/main/09/04/30/windows-7-whats-the-difference-between-the-editions
1. Run many Windows XP business programs in Windows XP Mode (separate download). [attachment=109591:win72_(Medium).PNG]
2. Connect to company networks easily and more securely with Domain Join
3. In addition to full-system Backup and Restore found in all editions, you can back up to a home or business network.
Edited by rotor123, 19 October 2011 - 12:32 PM.