Yes system restore must be on to do a restore point, but not to do a repair install. I see people come here with it off and suffering the consequences and can't figure out why they would ever turn it off. It's too late now if it's been off. There will be no restore point to revert to.
A repair might do some good but remember you'll lose a few things from a repair like all updates, added service packs, .Net Framework, DirectX 9 will all need to be re-updated, etc. A repair will put the operating system back to the state of original install but all programs will still be there. Some won't work until things get updated again so don't be discouraged if a few things act weird after the repair is completed, just update when done.