If you only have 512mb RAM, I would not under any circumstances install HP's printer software. I've seen it bring a 3GHz P4 with 1GB RAM to its knees, to where it took 20 seconds to respond to a mouse click, and an equal time to draw a dialog box.

The printer itself doesn't need the full software suite; it just needs the basic driver. Windows may already have a driver for it; if not, search for JUST a driver for that specific model -- this will be a small file, a few megs at most. This won't give you "features" like notifying you when a cartridge is getting low; OTOH you won't find it refusing to print because it believes a half-full cart is "empty". (This is much of the function of current "printer software" -- to waste ink, so you buy more ink.)

The actual driver will be on HP's install CD too, but you'll have to root out which file and do the install manually (use Windows' "Find New Hardware" or whatever they're calling it now, and point it at this file). If you're unlucky it's compressed into something normal humans can't get at, to force use of their installer and full software. (If you're REALLY unlucky, the printer is rigged to refuse to play nice without their fullscale software.)

"Readyboost" sounds like it's using a USB device as a RAMdisk (fake hard disk) for the swapfile ("virtual memory"). Probably wreaks havoc on performance, given how slow the USB connection is compared to the rest of the computer, let alone compared to actual RAM.

Dells don't use some special memory; the notion that you have to buy it from Dell exists only to make you pay 4x as much for the very same RAM sticks as you can get anywhere that sells RAM. It just has to be the same type, which any competent RAM dealer can check from the numbers on the existing sticks. Check your manual to find out what the max size is that the motherboard can handle, tho -- there are still a few namebrand machines out there that have very low max RAM limits. However, if you can increase RAM to 1GB or better yet 2GB, you'll substantially increase its overall performance, especially with Vista or Win7. Far cheaper than buying a new machine.