last week i bought a second hand PC for the office at work, paid £80 for it, 2005 i think, Pentium P4 CPU, 2 gig of ram, shitty GFX card (£10 lol) with keyboard and SHITE mouse ................
Oh, and a HP 1907w monitor i think it is, 1440x900 and it's running windows 7
£80 all in ........
I dont know how old your set up is, but an old PC isn't worth much, maybe £40/50 for a working tower, unless it was a HIGH END PC when it came out.
This is just my view, and i may be way off lol, be interested to hear what other people value it at.
