I enjoy building and upgrading PCs - I recently put together a system for £154 - using some bits and pieces, a few new parts and some ebay purchases - spec. is:
2.4GHz Athlon 64 X2 (from another PC I upgraded to 3GHZ part)
4GB RAM (ebay, £36)
ASrock mobo (new, £55)
256 MB Nvidia 6200 (ebay £8)
80 GB & 1TB SATA disks (one old, one new, £45)
A-Open case (new, £10 - ebay)
I got a couple of CD/DVD drives spare, plus a Creative Audigy sound card that I salvaged from a dead PC I was given (the CPU and or motherboard had failed), together with a 500W PSU.
It's running W7 pro (£38 student price - as it's for one of my boys) and Office 2010 pro (£39, as above).
Keyboard, mouse and monitor were also spares.
My sister replaced her dead PC (see above

) with a perfectly good generic PC from ebuyer for the princely sum of £249, delivered. 3GHz Core 2 duo, 8GB RAM, 1TB HDD, 256MB VGA card, Win 7 HP. She already had a nice LCD screen, so didn't have to shell out for that.
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