much slower pc after format

[CPdumb]

ok.. i had a trojan on my pc that i just couldnt get rid of so i formated my pc.after that i installed the windows updates and i noticed load times were much slower.i cant even play my online game anymore(Americas Army Operations).the games loading time is way longer that before the format.i get to the server browser and i click refresh then my pc freezes.ive tried vid card updates,defrag,im also having a problem with my internet.when i load websites sometime i have to refresh 3 or 4 times.and it still doesnt load the pictures on the site. here my system specs...

MotherBoard MB, Kenora,GB,GA-8SIML, R.2.0 SIS 650,w/LAN/Vid

CPU Intel P4 1.6Ghz 256K L2 478FSB PPGA

Memory Mem 512MB PC2100 DDR Spectek P32M6416HH7-75A

Hard Drive 40GB 5400RPM 2mb IDE ATA100 WD400EB

CD Rom CDRW 32x10x40 LG GCE8320B

Floppy Drive FD 1.44 ALPS DF354H090F Grey

Video Cards GPU,64MB DDR Prolink G4 MX440,TV out

Power Supplies PS, 250W ATX Switching SPI FSP250-60ATV

Operating Systems OS, WIN XP Home English Manual & COA Only

Operating Systems OS RCD WIN XP Home Eng. STI, V1.2

im not the most computer savy...could i have done something wrong when i formated?? i have no clue . any help would be greatly appreciated :-|
oh yea programs ive installed recently..
zone alarm firewall
spysweeper
ad-aware SE
messenger
army ops
and norton

[Catweazle]

Did you install all the drivers after you reinstalled Windows? It sounds very much like you've not installed your motherboard drivers.

[CPdumb]

ok i downloaded the the file with the motherboard drivers from the manufactures website.. now how do i install them...ther is a bunch of files but i can find and run or install file...(also my friend said if i install my vid card drivers before the motherboards drivers it may cause problems..is this true?)

[CPdumb]

ok i unistalled my vid card drivers .. then install the motherboard ones.. and reinstaled the vid card drivers and it still the same.. oh yea another weird thing that happens is msn messenger will try to sign in for like 30 seconds at boot up.. but then it stops.