Windows 7: ideas for a spare computer?

i just built a computer with parts my computer teacher was giving away and i have no idea what to do with it. i was more interested in the act of building than actually having a computer around (i love working with that kind of stuff). so right now i have an extra computer sitting in my room with no real idea what to do with it. really the only thing i thought of doing was selling it craigslist because i owe my parents a LOT of money (my last computer endevour got really out of hand and i owe about $460), but i'm not sure how much i can get for it. anyway, here's the specs if that helps anyone's suggestion:

3GHz Pentium 4 (possibly a dual core, i'm not sure)
2GB DDR-800
GeForce 8600 256MB
120GB IDE hard drive

the one thing is that it doesn't have an optical drive. originally, my teacher was only giving out cases and didn't want us to take any other hardware like drives. he eventually decided to give out more stuff, but i was out sick that day and kind of had to bug him a bit to let me take a board and cpu and i had the other parts except a DVD drive. so if i want to put Windows on it, i gotta find some way to install from USB. otherwise, i might put Ubuntu on it since that's easy to install from USB. not sure why i went ahead and typed most of that since it turned into a rant, but whatever lol. thanks in advance for your suggestions.

You could turn it into a small server and load windows server 2003 or 2008 on it. Then hook it up to your network to store and share files across your network.

i thought about that, but then i realized that nobody in my house needs access to anyone else's files. and if we do, the 2 main computers in the house are running windows 7, so we just use homegroup.

Sell it on eBay, only remember to claim it's a quad core...

lol that's an idea. i'm not sure how much i can get for it without a DVD drive though. that's kind of important. also, i'm not even sure if i want to sell it. not because i don't think i can get anything for it, but because i don't want to give it away. i'm attached to my computers, what can i say? xD

DVD drives are only about $25...so that's no big deal.
Based on the specs...you might be able to get about $100-$150 out of it.

Rather than install Windows Server 2003 or 2008 (which unless you have Technet will be expensive), load Linux to it instead and use that as a server. It will be far better suited to the hardware and far less expensive.

I don't see any problem with installing a Linux Distro and having a play around with it.

Are you highly experienced with Linux?

If not it's worth using it as a learning computer, just play around with Linux, the experience is priceless.

Never know, might come up handy for a job or a promotion sometime in the future.

Seriously... whack in a large pair of RAID mirrored drives, and a gigabit
NIC card, or two, and make yourself an NAS file server

i've used ubuntu before, but it was mainly just to play with what was once called Beryl (i think it's called Compiz now). it confused the hell out of me lol. i'm not good with terminal commands :/ as far as the DVD drive goes, i have no money and no money coming in. like i said, i owe my parents a lot of money and they're holding my allowance to help pay it back. plus i don't have a job and in addition to the computer payback, my cell phone bill is also getting tacked onto that for each month. so i probably won't have any money for quite a long time. and i really don't need a server. my hard drive is big enough for anything i really need. and for the spillover, i have an external hard drive.

Hmmm, try a different OS, i think there are other OS's out there, that aren't mainstream, but there out on the internet somewhere, have a play around?