My brother bought a quality computer from cyberpowerinc.com (pretty much a clone of ibuypower.com... or maybe vise-versa)
Its a great computer, with awesome stuff, and he got it at a great price.
you can save money if you dont get a monitor or speakers and just keep your old ones.(if you think yours will do teh job)
those two sites use nothing but components that a person making their own computer would use (give or take some catagories) so its like having a "homemade" computer, but someone built it for you.
I build my own computers, so i probably wouldnt ever buy from there, but someone looking for a good, reliable, cheap system built from quality parts from the major hardware brands out there, who doenst know enough to build their own, should really check out cyberpowerinc.com and/or ibuypower.com
as for your current computer, you could reformat (using a retail OS, not your OEM one), maybe get a good virus scan, upgrade to some high quality memory and some anti-spyware programs, and run them everyday. It could help your computer last a bit longer.
I feel your pain tho, man. we had a compaq that was the same way. 633mhz celeron with cheap memory, a small hard drive, and EVERYthing was built right into the motherboard. if you get really aggrivated, try punching pillows or something while you do a nice, clean, cold-boot.
You're the guy from that hamburger train, right?