Windows 7 was already installed on my laptop. I installed Ubuntu 12.04 by dual boot partition, but when I start the laptop I get both Ubuntu and Windows on GRUB. When I click on Windows it doesn't start, and it says Windows needs system repairs (it starts repairing and then the computer is automatically turned off). Ubuntu works fine, but I can't view my windows C drive files in Ubuntu (which are saved on the desktop in Windows 7). Can you help me out with this? I don't want to lose my data on Windows.
For your case, your Windows boot files are probably corrupted, see other options and start from "repair windows boot files"