Controler Software

I've built my contraption and now want to fire it up and make
something.

It's a router, 48" square & 5" Z axis. I plan to drive with a Pentium
II, 450 mhz, currently running '98. I'm not having good success with
anything I've tried yet; because of the machine belching and crashing
I'm willing to consider anything, but I want to get this resolved
once and for all and avoid having to continually upgrade.

I'd like your opinions:
What is the most economical and stable controler? Should I install
Windows 2000, or Linux? What sort of output can one realistically
expect from this machine?


Thanks.