D845GVSR. Help me!

I have got a Intel D845GVSR, 1.8GHz, 256MB, HDD: 30GB Maxtor and 40GB SamSung, 1 FDD, 1 CD-ROM ASUS and I have a Internet connect at home. I often run McAfee to scan virus and spyware. But it makes my PC slow. How can I make my PC faster and faster? Thanks.

That comp needs more ram. You could upgrade the cpu as well.