Apps won't matter. Info relating to your downloaded apps is saved in the cloud so nothing on your PC. Media (music, video & photo) is another story. Unless you move your folders intact from one PC the the other, syncing my her confused. I would definitely sync the phone with the old PC just before you trying syncing with the new PC, as things like your Camera Roll photo color may get overwritten in the process. I plug my phone into two PCs, and Zune launches on both, but only sync to one PC, so not sure exactly what will happen.
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