Ok guys firstly some bad news
Pentium 3's had two sockets commonly used during the lifespan - I believe the chip you are talking about is a socket 370.
Pentium 4's used sokcet 423 / 478 / 775 none of which work in socket 370 boards
Thanks for saving me from wasting time. I checked my service tag at Dell and got the following for processor.
9K795 Processor, 80532, 2.0G, 512K, 400FSB, Socket N
Does this mean it is 423/478/775 type ?
Thanks again for your responses.