celeron 800 isnt bad
ok pa yan for basic computer use, wag lang gamitin for gaming
pwede pa yan for office, internet, etc
para sure ka na malinis ang pc and mabilis, format mo muna, start from zero. anyway, parang d mo na rin gaano ginagamit so its better to start from zero again from that pc
try to have at least 256mb RAM (the bigger the better)
have a bigger virtual memory (set it to manual rather than let windows decide)
limit the number of programs you install. only install those that you will need to use
sa pc ko before, celeron 900, 256mb (shared video), i am able to play games like civ3, at the same time no problems with internet and office programs