If you've downloaded Windows 7, it's a good idea to create a system repair disc straight away in case you run into problems booting the OS later on. Open Control Panel -> Backup and Restore -> Create a System Repair Disc, and let Windows 7 build a bootable emergency disc. If the worst does happen for whatever reasons, then it could be the only way to get your PC running again. Startup Repair essentially just scans your computer for the problem and then tries to fix it so your computer can start correctly. Though it can’t fix hardware failures, such as a failing hard disk or incompatible memory, Startup Repair does a good job at fixing certain problems, such as missing or damaged system files.