Hi,
Just to confirm - ( If you decide to upgrade the RAM )
Your motherboard only supports up to 4GB RAM.
The suggestion is 2 matched pairs. ( You have 4 slots - probably 2 different colours. )
The first pair will be in slot 1 & 3 and the second pair 2 & 4
You would need 4 x 1GB DDR2 RAM 533Mhz
32bit systems will only utilise about 3.5GB RAM anyway.
If you are unsure try Crucial Scan
http://www.crucial.com/uk/store/drammemory.aspx?gclid=CMywhJq9ya8CFQ1lfAodo08OZQ&cpe=pd_google_uk&ef_id=edNPAtrvwkcAAEX@:20120422221303:s
How much RAM do you have at the moment?