Three installations of XP on the same partition is a hopeless situation. Your "new windows" will never see the program installations on the original, and if you were to contact Microsoft for assistance with this they have just one stock answer - reformat your hard drive. I cannot understand why you tried other copies of XP, as well as being illegal it was bound to lead to this sort of problem. Also why was it necessary to write the product key on the XP disc. Its plain enough to see on the sleeve it came in.
So you have only one option - reformat, despite the consequences. If your cd came with your system (OEM) you can try the vendor for a product key if you still don't know it. If its retail contact Microsoft on 0870 60 10 100 and tell them your situation. The same goes for your Office discs. They are always sympathetic, and will ask a few questions, and if satisfied will issue new product keys. But, if there is anything "dodgy" regarding these discs I wouldn't bother. You will have to purchase anew.