Is this a brand name PC like Dell, HP and Sony? Is this a laptop or desktop?
Normally in any PC (retail - store bought), you have a primary C: drive and D: drive where hidden recovery OS is located. This gives the owner 2 options to restore the PC to factory new condition - the day it was taken/opened out of the box. One is using the recovery partition (D: drive) and the other is using the recovery disc's the new owners make.
One should really not move partitions around - adding or making new partitions, if one is unsure of what they are doing. This can lead to a botched up OS. Then you would need to re-install the OS using the above 2 mentioned methods to restore the PC to it's original state