Merged the above posts - Stoaf88, please tell me (I am trying to get attention to this thread so people post questions such as yours here, rather than make new threads) - how did you decide to make a thread titled "2 quick questions" rather than ask them in the "Quick Questions & Answers Thread"? Did you simply not notice this thread? or did you see it, and decide not to ask here? seriously seeking opinion, there's a very good chance (if it was a busy day) - your thread would slip to page 2 and never be answered, which is why we prefer them here.
Anyhow, 1: - already answered, ty Fozzy.
2: That is a seriously aging CPU+mainboard - I had one myself, it died ~12 months ago. I doubt you can find a "socket A" CPU to fit your board these days, other than on the second hand market - and I hate buying used CPUs
The results won't be too great either, at best a 30% performance boost - not enough if you are hitting 100% on 5 tables already.
I'd recommend get a new Motherboard + CPU, based on the old socket 754 (with a 754 AMD Sempron) or socket 939 (with an AMD Athlon64) if money is very tight, as this would allow you to re-use your DDR memory.
Otherwise, get a new (Socket AM2) Athlon64 X2 CPUdual core + Mobo + 2GB DDR2 (costs <£100 for a cheapest here in the UK) - fit that in your existing disks / case etc, and it will be hella faster
Of course, if money is not an issue get a nice high spec new computer - but I suspect it may be, else you wouldn't be a) running a XP1900+ or b) wondering about upgrading its CPU.
Good luck,
dave.