No. As far as I'm concerned, you bought the software and you are using it on ONE PC. Microsoft may think different, but you should be able to reuse the same key. Sometimes changing the motherboard will flag the key and you'll have to call MS and explain to them that you had a virus and are reinstalling. That's what I do when that happens. I mean, I haven't read the EULA, but if you aren't making two PCs run off the same key, then you should have the right to replace/upgrade parts and still use that key.