Hi robt,
I have INTEL and AMD options.Its over your budget but I wouldnt buy anything less.I would really think about threwing in more money if there is a possibility.IN case you are really tightened to 240GBP then let me know and I will put something together but 240 is very tight.Its more for office PC then for home/game one.
INTEL option
Motherboard: MB MSI P6N SLI-FI, nForce650i SLI, 2xPCIe, GbE, 1394
CPU: Core 2 Duo E4400 (2, 0GHz, 2M, 800MHz) Box
Memory: 2x512MB DDR II 667 A-DATA Retail double pack
Graphic card: VGA MSI RX1950PRO-T2D256E, 256MB GDDR3/256b, 2xDVI
HD: WD800AAJS CaviarXL, 80GB, 8MB, 7200rpm, SATA/300
Power supply: Tagan TG480-U01 480W ATX2.0 SLi Compliant Silent PSU
Case:Thermaltake VC2000 Mambo
Should be around 390GBP but would be really good investement.
Fast CPU,1Gb of memory is pretty nice for WindowsXP,the above graphic card is the best bang for the money on the market now now and very silent,same sized HD but will be much faster for the system,decent power supply(not overkill) and the case is pretty cheap one but its very well built and really looks nice and decent for the money.
You can still re-use or old HD and CD/DVD drive.
AMD option:
Motherboard: MB MSI K9N Neo-F, nForce 550, DDR2, GbE, SATA-II, RAID
CPU:AMD A64 X2 4800+ EE (socket AM2) Box
Memory: 2x512MB DDR II 667 A-DATA Retail double pack
Graphic card: VGA MSI RX1950PRO-T2D256E, 256MB GDDR3/256b, 2xDVI
HD: WD800AAJS CaviarXL, 80GB, 8MB, 7200rpm, SATA/300
Power supply: Tagan TG480-U01 480W ATX2.0 SLi Compliant Silent PSU
Case:Thermaltake VC2000 Mambo
Pretty same stuf except the AMD CPU and motherboard for that processor.Price estimated 350GBP.Also both systems are dual cores.
As I said if you really cant spend more then 240GBP I will post something later to meet your requiremets but my suggestion would be to spend more.I did that to all my "customers" and they were always happy.Their child as well
P.S:sorry for my english grammar as I know there are a lot of mistakes above but I spent today a lot if time on the phone to fix some issues and talked all the time in not my native language.I am really tired now...