Just had a busy week, so I have only got time now to post my answer to fix the problem
Basically, the surface pro 2 wasn't able to log in for some random reasons. It just gave me black screen. But I was able to use the cmd thanks to windows 10.
Then I inserted an external hard disk and used the command prompt to copy the entire C drive to my external hard disk. Thank god it worked!
Now, I think I'm gonna find a time to reinstall windows and hopefully the surface will still be able to function normally! (Just bought a macbook real cheap so I'm not in a rush)
Thanks again guys for helping out! Cheers