Well you can't really say you've got a slow motherboard, old perhaps
but the motherboard is only one of a few parts that determine your system speed. Mainly you gotta tie the CPU, Motherboard, and RAM into the equation as far as the computer speed as an entirety goes.
I'd suggest you try and read about how exactly the motherboard works so you can get a better idea of what you want/need out of your system.
You can buy ANY motherboard you want for your computer as that's basically the starting foundation. BUT, you can't just buy a motherboard and throw it in. EVERYTIME you put in a major piece of hardware such as the motherboard, you ABSOLUTELY 100% HAVE TO NO QUESTIONS ASKED, FORMAT YOUR HARD DRIVE. There is just no exceptions with this. If you don't you'll get errors galore and instability up the butt like you wouldn't believe.
Now, once you've got your motherboard picked out, then you gotta get a good processor. Currently if you're going AMD, but don't want to go to the 64bit processors, then you need to look for a 400FSB Capable motherboard. This is where you need to start, get nothing less than 400FSB.
The newer motherboards have 800FSB and 1000FSB, but that's the AMD64 bit chips and the Intel boards that are for the newer P4's and of course the top of the line P4's.
I suggest you look into ABit or MSI as a motherboard manufacturer as either of those companies will offer good quality made boards with good stability. That board in the link just comes boxed with the processor so god knows how good or how stable it'd be know what I mean?
Also if you ever look into the world of overclocking you can get a chip that has like 266FSB and along with a good overclocking motherboard, you can still obtain the same speed like 2GHz, but make the processor work at 400FSB instead of it's normal 266FSB, but that's getting into other things
Pick a motherboard with 400FSB, like I said I suggest MSI or ABit as a manufacturer and you'll be looking for a Socket A also sometimes seen as Socket 462 because 462 is the amount of pins in the processor. So Socket A = Socket 462 just incase you see either of those, so you don't think they are different and get confused.
So you've got a 400FSB capable board, then I suggest you look for a 400FSB capable CPU, which will probably be like $150-$180 for that. This is where overclocking is nice because you can get an $85-$90 chip and make it as capable if not more so than a chip that costs twice it's price.
If you get a CPU with less than 400FSB, you're not slowing down your motherboard in anyway as it mainly relies on the communication between the peripherals to give you your speed. So it'd be perfectly fine putting in a 333FSB CPU into that board, but you're not using the board to it's full potential.
400FSB RAM is known as PC3200 because it's stock speed is 200MHz, and since it's DDR meaning DOUBLE data rate it's 200x2 = 400 so that's how you get 400FSB in that scenario.
So with a 400FSB motherboard you'd want PC3200 RAM to use it at it's full efficiency, but then you'd also need a 400FSB CPU otherwise you'd have a bottleneck between the CPU and RAM which of course results in performance loss.
After (if) I install a new motherboard, how will it affect my computer? Especially in gaming? I'm looking foward to buying at least a AMD Athlon 2500+ motherboard and cpu combo. And is it easy to apply or do you definatly need a computer technichan to apply it for you?
Depends on what you're coming from. If you had PC100 or PC133 RAM before then going to a 400FSB motherboard with say PC3200 RAM or even PC2100 for that matter would smoke your previous setup so you should notice a nice increase in smootheness and speed.
It's fairly straightforward and easy to put in a motherboard and seat your CPU, but it doesn't sound like you have too much experience in this so it's either pay a technician, but you don't get to learn with that, which learning is better, so if you have a friend that can build it and show you how to do it that'd be the best.
Or you could simply READ READ READ like a madman and attempt it on your own. It's not very hard, but impatience is the main reason why people screw up their processors and/or motherboard.