[Red Moon]

Sounds like what might be in order is a full reinstallation of Windows XP.

However if your looking to replace it and your willing to re use the screen and keyboard you should be able to pick up an Windows XP machine for about £200 and buy a plug in modem for about £6.

Here are a couple of links:

£200 - Windows XP Computer
£6 - Modem

In theory if you take XP off the old machine you can use it on the new one, but you would have to check with MicroCrap. If you can you can save even more:

£140 - Computer (No Operating system)