No each type of ram is different, it wouldn't even fit in the slots, nevermind use it. To upgrade to a different type of ram you'll need to get a new motherboard. Unfortunately there aren't many motherboards that'll take your processor any more, unless maybe if you try to get a second hand one.
Here's a link to one, there may be a few more available elsewhere thoughhttp://www.ebuyer.com/product/179185
If I were you I'd think about building/buying one with a newer processor. If you decided to build one yourself, then you could get a new motherboard, ddr2 ram and a new cpu for about £150 and use the other components from your present system ie. case, dvd drives, hard drives, although you may have to get a new power supply if your current one can't supply enough power, that would add another £50 for a decent reliable one, go for a decent make like antec or ocz
Obviously I'm in England so it may be cheaper or more expensive depending on where you live. The links below are for an example of what you could get if you decided to build a new one.http://www.ebuyer.com/product/245670
- Antec 400w psu £47.43 may not be needed thoughhttp://www.ebuyer.com/product/200938
- E5500 2.8Ghz dual core processor £49.40 http://www.ebuyer.com/product/168935
-Asus P5KPL-AM EPU motherboard £31.98http://www.ebuyer.com/product/166785
- Crucial 4gb ddr2 800mhz ram £58.75