Would I Be Able To Run A System Restore To Downgrade Windows 7 Back To Vista?
Basically, someone has given me a disc to test Windows 7, but if i don’t like it, will i be able to downgrade back to vista via System Restore, or can i just uninstall Windows 7?

To go back to Vista, you’d have to (1) Install in a dual boot scenario, or (2) make a backup image of your Vista install.
And system restore does not make a full backup image.
When you upgrade Vista to Win7 any old restore points are deleted as they are no longer valid. You will have to reformat and reinstall vista if you want to go back.
If the disc didn’t reformat your hard drive in the process of installing Windows 7, then you’ll be able to restore Vista.
As far as I know, system restore cannot revive previous OS’s installed on the pc.
No you will have to start over