If you remain focused on the D610, a decent laptop for most folks,
then Fill the memory slots to 2 Gigabytes, and upgrade the hard drive to a Seagate, Western Digital Black, Samsung, of Fujitsu 250 GB to 320 GB... both sizes are quite reliable now.
Shop among the popular sites: Directron.com, NewEgg.com, TigerDirect.com, Frys.com, PCMall.com, Krex.com, ZipZoomFly.com, and any other name sites... and get those with the lowest combined price with shipping.
You will need a #0 philips screw driver, and some rubberized gloves to keep static electricity down... along with a working space where you can take your time... along with a Dell recovery/re-install disk of Windows, and all the downloads from
www.Dell.com support for the product ID on the bottom of your computer.
Avoid Hitachi and other brands not listed above... The ones that come in a box, are more expensive but give you extra ease if you wave warranty issues. But the bare drives wrapped in static free plastics are every bit as reliable, and prices are much lower...