Hi,
Some general thoughts:
You are going to have fixed costs of the following no matter what system you build.
Case and Power Supply: $75.00
Hard Drive: $50.00
Windows: $80.00
Ram: $40.00
DVDRW $40.00
CD/ROM or DVD/ROM $22.00
That is approximately $300.00
You probably can get a cheap case (Rosewill el cheepo for Newegg or Chiefvalue for $35.00 dlvd comes to mind but I just would not go cheap on this)
You probably can go without the 2nd optical drive.
But assume we are basing this on $300.00 we need to add mobo, processor, video
Assuming you are willing to not buy new the best way for you to go would be Socket 754 with a Sempron 3000 or 3100 which I would buy on the F/S F/T board here. You can pick one up for around $65-75. Then buy a motherboard with onboard video. The Biostar with the 6100 runs around $60-65.
This gets you to around $450.00
Figure you are going to take at least a 25% hit on your system selling it if you bought retail. This will get you back around $575.00 I am doing this in general terms because you can obviously reuse case, windows, burner, etc.
The components of your system that will be sold to downgrade will be the CPU, MOBO, VID CARD. But the vid card you should just return anyway. So it is just really replacing the CPU, MOBO combo with another CPU, MOBO COMBO and figuring out what to do with your extra 512 of ram.
In the end I think you gain around $100-130. assuming your mobo, cpu cost you around $240.00.
Not sure if it is all worth it.
BUT!!!!!!!!!!! You can do what I do for my friends and family who want inexpensive systems. I buy the Rosewill Case. I wait to buy Hard Drives when rebates are running. I buy the mobos, cpus, ram on these boards. The only thing I buy retail (From Newegg) is the NEC DVDRW burner and a CD/ROM.
You can even use a Socket A system that will cost you around $90.00 for cpu, mobo on these boards. Right now someone has an XP 2400 2.0ghz processor for $45.00. Someone has an N-Force 2 shuttle board for $40.00. THAT IS A GREAT LITTLE SETUP THAT WILL DO EVERYTHING YOU WANT.
Just my 2c