Before you dive into a full rebuild could you tell us what aspects of the machine are actually below your expectations?It might well run without having a computer attached.The Isel brand has been respected in the CNC world for quite a while and it looks as if the machine was constructed to their usual standards and doesn't seem to have suffered any obvious damage.Could you post an image of the control that came with the machine?I wouldn't be hugely shocked if there was a slot for a floppy disk somewhere.It might be that with a tiny amount of additional hardware in the controller,you could save a lot of expense and work.

Useful additional information would be whether you have any amount of CAD/CAM experience or have operated CNC routers in the past.Do you have any of the software to create the programs?It might seem a bit intrusive to ask these things but it ought to get you a response tailored to your level of understanding.If you didn't get any manuals for the machine it might be worth asking here and on the Woodweb.com CNC forum as a manual would have schematics and possibly a lot of other useful information.There might be a nameplate with model type somewhere on the machine.With this information you can determine whether any new parts would be enough of an improvement to justify all the work involved,even though it would be a valuable learning process.