Slow computer

I bought a computer about a year ago and it’s working incredibly slow. I had a few viruses because i don’t use protection and keep getting random issue with it so i re-install windows which helps but my computer still works slow. I reformat the harddrive with my Windows XP cd but it doesn’t work like a fresh copy.

Specs are
Dual core 6420
2gb ram
Gigabyte S-series 965p-s3 m/b
400gb hardrive
EN8600GT asus card