Stay away from DELL
I work at a university that has HAD (Past Tense) an almost exclusive relationship with DELL. For the last couple of years, we have had a spate of hardware failures. Granted that they are covered by the warranty, but the sheer frequency with which they fail, kinda flusters us. Early this year, we shifted to COMPAQ/HP and we have drastically reduced our problems.
The earlier suggestion has a lot of merit. If you can build your own PC then go for it. If you pace yourself carefully, then you can have a bargain PC. Don't go for the whole shebang. Limit yourself to a darn-good MB, CPU, CASE and Power Supply and atleast 512MB RAM. Forget about the other devices if you have any like used device from your old PC. If you have an old HD, use that. Likewise for the CD-ROM. You really don't need that souped up Serial ATA HD or that DVDRW right away! Or, do you? By the time you have a fair idea of the capabilities of your new hardware, the price of these components would come down drastically, and you would be able to pick and choose newer/better ones.