I have a desktop pc which keeps on looping instead of loading the operating system. Is motherboard is MSI H61M-P31(G3).Previously it was running on windows xp service pack 3 and after a power failure it displayed some information promting me to repair some corrupt boot file but it could not repair it using the original win xp disk, then I disconnected its hdd and installed windows 7 ultimate on it using a different computer. After a successful installation of win 7 I connected the hdd to its original system unit but it could not load the OS instead it keeps on looping ie when I launch start-up repair it shuts itself down after finishing.When I start windows normally it takes me back to "launch start-up repair and start windows normally ."
Can you boot into safe mode? What about by-passing the boot process and go into recovery mode? My guess is that you may have system damage other than just the disc. Often power failures are also accompanied with a power surge, damaging other components unless you have a newish, good surge suppressor, or a UPS that your system is attached to. For my system components (including laptops when tethered at home), I have them all connected to an industrial-class UPS that has serious surge suppression capabilities. As a result, I have never had such a problem.
then I disconnected its hdd and installed windows 7 ultimate on it using a different computer. After a successful installation of win 7 I connected the hdd to its original system unit but it could not load the OS instead
Moving hard drives between computers doesnt always result in the OS coming up smooth and finding new devices and installing drivers. That only works well on very similar hardware. In addition, depending on the licensing you have, you may be prompted to re-activate with Microsoft.