Please first explain why you tried system restore. Was this because your systen was very unstable for example?
I don't know why system restore lasted so long and was in some kind of loop. What I know is all systemrestore actions are done in 1 transaction. So it succeeeds or it fails. There is no thing as a half restore. But ... harddisk can errors... or system was damaged during last startup. Don't know what happened!!
Do you have a windows x64 system repair cd, or Windows 7 x64 installation dvd?
Or just start up your pc and press F8 multiple times (1 sec in between).
perform a "system restore" from there
System Recovery Options