can i upgrade my MB without needing a new reg # fom Microsoft? and i have a hp here is the pc my pc i am upgrading. on the pci slots in the rearof the pc it don't have a agp slot at all. and i have only 3 pci (full ) but i have 4 slots in the case.
Your gonna have a bigger problem with HP then Microsoft. There is a number of times you can reinstall XP and the activation will work over over the net. If not you can simply call them up (its a 1-800 number and they'll provide a number that must be input to activate - this is free) However if you have an HP recovery CD it will not likely work with a new PC because the CD is most likely branded. You can then use any other XP Home CD and your Product key for your XP and its still legal.
Here's the biggest thing. Don't just upgrade the mobo, get a new CPU and RAM too. And a powersupply and case. Your mobo and CPU are socket 370 - max upgradeability is P3 1.4Ghz. And it uses SDRAM and not DDR. A celeron 1.3 is not going to do it for much longer with new games and I'm assuming thats where you're going.
wll games aren't really what i use my pc for.. i use it for web and graphics. 3d and photoshop. i only play one game UT. but i am thinking of battlefield 1942. but i just upgraded my ram to 512 and don't wanna lose all that money because the pc133 is no longer backwards compatible so the pc100 costs quite a bit.