Nah, they had sound
Weeeell... If it's supposed to have sound, but doesn't, that could be fiddly. If it's just never had sound, less fiddly. You could get a DVD player for under £20, no probs, and a cheap soundblaster card of some sort for much the same... And I suppose, you might need speakers too
This stuff is all fairly easy to set up, assuming your PC isn't way older than I think it is. Hard drives are easy enough too but you need to know you're buying the right thing, for which you really need to know exactly what the motherboard is.
But then, there does come a point where there's no point in upgrading, to be honest. I'd watch it though, most of the really cheap PCs scrimp big-style on hard drive space and RAM, a small hard drive's easy to upgrade (just add another) but it's something to budget for. My MP3s take up 80gb, frinstance, that's the entire of the drive that came with my PC
