Was trying to install a nice pretty dark theme for windows 7 that requires replacing some dll's in windows to allow for much more customisation with windows themes to do so.
So i did that, then tried to restart computer, and get loads of errors in LoginUI.exe about a procedure entry point not being found in KernelBase.dll which has to be clicked like a million times to continue, and of course after manually rebooting i cannot get into windows, EVEN in safe mode.
Thankfully runing safe mode to command prompt worked (After clicking okay on that error about 1 hundred times) and i managed to change the dll's back through command prompt! and all is well now
If i hadn't been able to do that i'd've needed to reformat windows 7 and then request a new serial from uni since i got it through MSDNAA