Urgent Build, Please Look.

Well, the story is a mix between sad and pitiful. I have a friend who's working on about a 10+ year old computer to game with. Considering I recently rebuilt mine, I decided to use the old parts, fill in the blanks and upgrade here and there to put together a modest PC for him. Where it all falls apart is I didn't seem to pay as much attention, and now I sit on a few incompatible components. I am here, hoping that some souls can give me advice on the route to take, in both financially sound but at the same time not giving my friend another dinosaur. Below is a list of what I have, old and new. I thank you all in advance.

Old Parts:
- An old DVD-RW, can't recall the make as its a touch faded.
- A gigabyte N650SLI-DS4 motherboard.
- A few variations of 1gig ram, mixed bus speeds from 533 to 667 I believe.
- A 200gig Segate 7200 RPM hard drive.
- A Intel dual core at 1.8 something or another.
- A Cruiser X case that has some issues with the standoff mounting holes being stripped.
- A Corsair 650w modular PSU.

New Parts (What I tried to boost my friend to):
- A Q9300 quad core at 2.5ghz.
- 2x2gig of Gskill DDR2 800 ram.
- New heatsink for the processor.
- An Antec Illusion 300 case.

If wished, I can get links up for the items or try. The main goal here is to build something or retrofit something budget wise, but I don't want him to carry another ball and chain for 10 plus years. Something modest and usable in today's standards, with a little more expandability in the future. Thanks again.