I used to run out using XP with 4gb ram (3,5 usable) , so i would increase it. I am surprised he has 4 slots:
DDR2 PC2-5300, DDR2 PC2-6400
Memory Type: DDR2 PC2-5300, DDR2 PC2-6400, DDR2 (non-ECC)
Maximum Memory: 4GB
Slots: 4 http://www.crucial.com/upgrade/Dell-memory/Inspiron+Desktops+/Inspiron+530-upgrades.html
2GB DDR2 PC5300 PC2-5300 667 Mhz LOW DENSITY Desktop Memory http://www.ebay.com/itm/like /370556236203?lpid=82
US $20.45 FREE Standard Shipping
Now I am curious. I never noticed the other two slots. I’ve had the cover off many times doing cleaning. 4 would give me an extra GB possibly 1.5 more. I know I had 4 GB put in my laptop at the factory for any future OS upgrades. Could have been this one I knew I could do it later by putting 2-2GB sticks in. I’ve slept since then LOL.