Fix broken registry startup error?

Hi,
Recently my custom-built pc has come across an error where it at boot-up it says "windows has detected an error and canceled startup to prevent system damage".

I am pretty sure that this is a registry error because of what happened before, heres the full story.

I first had to delete a couple game files from the registry of my computer because they had been corrupt to the point where the uninstaller was missng but some files were still there and the game was still installed, so i had to manually uninstall the game. I followed steps from a online source and made sure that i only deleted the files specific to the game and not to touch anythign else. After doing this i rebooted and my pc was still workign fine. Then, i opened up my registry defragger (glary utilities) and ran a registry defrag. It told me that it would clear up 77% of the space(i hadnt run it before and i built my pc about 5 months ago) but i ran it anyways. After the auto reboot after defragging it came up with the error message and no longer starts windows. I had backed up my files with Norton backup but was unable to do a system restore because it said "you need to have system protection enabled on drive c", i only have one hard drive with both windows and my data on it. It also cant find any system images to mirror and revert to. Windows tried repairng the errors but couldnt. It also scanned for any memory errors and found none. I have tried every option on the windows bootup system repair menu with no success.

I was thinking that i could take out my hard drive and plug it into a one of those devices that turns an internal drive into a external usb drive. If i were to do this and plug it into another computer, is there a way i can repair the registry? Does anybody know of anyway to do this or of any better solutions to this problem? Any help would be greatly appreciated. Thank you for your time.