So, I'm here to show you how to fix this.
Sadly, the most practical way of fixing this is through this little beauty:
(This is a Windows 7 disc, because I chose Windows 7 to demonstrate this tutorial.)
So, what you'll need is:
•A Disc drive preferably connected via SATA cable to your computer
•and the Windows installation disc that applies to the OS you have installed already on the PC
Step 1: Get to either your BIOS settings via hitting F2/F12/Delete while the computer is booting, or let your computer get to the GUI that I talked about above.
Step 2: Insert the disc corresponding to your current OS on the PC, in this case, Windows 7. After the disc is in the drive, press a key or select the disc drive in the BIOS boot menu to make the computer boot off of the disc in the drive.
Step 3: Wait for the computer to boot, and you'll see a screen similar to this one:
During this step, no user actions are required, so just sit back, and wait for Windows to do it's thing.
Step 4: After you've gone ahead and let Windows do it's thing, your computer should then display a screen similar to this one:
Now, just select your input methods, (language, time, and keyboard language) and select 'Next'.
Step 5: After you've selected your language and such, your screen should display the installation screen, shown here:
Now, what you want to do is select 'Repair your computer', shown in the picture above. This will only scan your startup files and replace what is needed, not install the whole OS.
Step 6: You should now get a dialog box telling you that the computer is searching for Windows installations. Here, you just repeat Step 3 and wait.
Step 7: After the computer has searched itself for Windows, you should get a dialog box showing you the Windows installations you have, shown here.
Go ahead and select the Windows installation you want to repair, and click next.
(The drive letter does not matter in this case, don't worry.)
Step 8: Now you'll get a dialog box telling you to select a repair tool. In this box, you'll want to select the tool 'Startup repair'.
Step 9: Startup Repair will now search your OS files for errors and missing or corrupted files. Now, do as we did in the steps that are multiples of 3 and just wait it out without touching anything.
Step 10: After Startup Repair has located problems or missing files, it will begin to repair those files and/or errors, so just continue to wait. Maybe grab a drink or a snack, because this may take a while. Also, don't worry. Your computer will restart multiple times during this process. Do not interfere with this process as it will interrupt the repairs.
Step 11: After you've relaxed a bit after your hard work, you may notice that your computer has finished repairing itself. When this screen shows up,
All you need to do is select the 'Finish' button to complete your work and boot into Windows.
(Don't worry, as it says above, repairs may not be successful and in that case, Windows will reboot into Startup Repair again and try to repair the corrupt files once more. If it does not work after many attempts, do a clean installation of Windows via the disc.)
Well done, you've repaired your computer!
Hopefully this helps someone, happy repairing everyone!