Hello... This is a problem that I've never seen before. My PC boots perfectly but when it reaches the windows 7 logo it sticks then restarts and it's a loop. I tried safe modes, last known good configuration and even repair from the boot cd. I tried to re-install windows 7 to the c: drive but its not being found, only the d: drive partician and then reserved is available. When I browsed for a loader in the operating system boot menu I saw my c: drive as "boot (x)" and the cd said the drive is lock please unlock it...

Can anyone assist me with this situation please?

You might need to replace the Hard Drive. It may be faulty, you should also see if the motherboard is working correctly. Try to boot up a live version of Ubuntu Linux, this might help you see if the HDD is OK.