The 5890/5972 will probably be your easiest route to take getting things working. Agilent has a spreadsheet that shows all the hardware and software compatibilities. You will probably have to find a computer running XP or older software to be able to run the older versions of MSDChemstation.

http://www.agilent.com/cs/library/Suppo ... F05030.pdf

Looks like the newest version to support the 5890 will be B.02. It says that runs with WindowsNT4, but some have gotten it to run with Win2k and possibly higher. You will be dealing with instruments that use the GPIB communications interface so that will also be something to look at.