Ducati Sporting Club UK > General > Technical - Help or Info - NON Motorcycle > PC/Internet speed

[psychlist]

I'm quite keen on playing games on my x-box/PC and one of them is a PC MMO-RTS where I get the chance to shoot anyone from anywhere in the world, good eh!?!
I've recently been experiencing problems where, after playing for half an hour or so, my PC starts getting synchronisation errors because it's getting "Laggy"?
My PC isn't ancient (yet), it's a 1.8Ghz celeron processor with 256k ram and I'm using Internet Explorer 5 over NTL's 300k cable modem. I'm concerned that it's not so much the internet connection but my PC that's slowing down?
How can this happen? More to the point, as a complete technophobe (I'd rather fight my way into one-piece leathers and fend off the DesmoDue racers into Paddock Hill bend) what can I do about it?
I've cut the other programmes out so that I'm just running Microsoft Spyware and McaFee virus software at the same time as my game but are there some settings I could try on my PC to stop it slowing to a crawl?