no, nowdays you can upgrade it with non-dell parts. as for building a computer...last timei did, it was an awsome computer, I had a bunch of troubles on it that i couldnt figure out, nor could anyone I asked or even anyone in the forums that read the posts I made. Pretty much I didn't get to use it much at all, I mean at all. The board may have been faulty, or damaged somehow while inside my case, or some other random thing. All in all, the thought of building computers or working on the computer I built just stresses me out. I was going to go Monarch but I can't afford them....I did find this for hp though:
http://www.compusa.com/products/product_info.asp?product_code=339560&Pn=Pavilion_a1520n_Minitower
This computer is genrally the same as the Dell I was looking at but it has lightscribe on the dvd-rw(lightscribe is kind of cool i guess, but I don't see myself using it much if at all), and 250g hdd instead of 160g(not a big deal as 160g is plenty of room for me already) and it uses ddr400(better then ddr2 533) which means its 939(I don't care about the socket, the biggest diff is that am2 has ddr2). But it is $140 more.....I will still consider it, but $140 is quite a huge chunk of money in my book.
As for the specs, the Dell looks like it has some good ones: pci-e, enough pci slots, nforce 430 chipset, dont care about the onboard video but its pretty good for onboard still, can handle up to 4g...
lol.....the research into buying a budget computer is long and tedious road, most benchmarks and reviews are on top of the line stuff and towards single parts vs. manufactured computers.