Agilent provided free A.06 software to apparently all users (at least to us)for Year 2000 compliance issues (Y2K). So my guess, and just a guess, is that anyone with a ChemStation license could legally load that version.
I have such A.06 ChemStation discs.
There are some questions: do you have a ChemStation license number (a 10-character combination of letters and numbers) ? Obviously your modules were ChemStation equipped (as that was an upcharge on 1050 modules), so someone was using them with ChemStation. Look for stickers with the license number on the module cases themselves; Agilent/HP provided about 6 stickers with the license number, and upon installation many engineers would stick those on the modules.
That said: most likely the license number of one of your existing 1050, 1100, or 1200 HPLC systems could be used. Maybe even Agilent telephone help could supply a universal HPLC license number.
OK, next question: what type of computer, and what version of Windows? We run A.06 (still) using Win95, Win NT4, and Windows 2000 professional.
There is a chart on Agilent Website about compatibility of versions, shows what they've checked out.
If you use Win95/NT 4 and a Pentium 1 computer (and maybe Pentium 2) you can use an 82335 HPIB (GPIB) card in the computer. If you use newer Windows and Pentium 3 or 4 computer (maybe even Pentium 2) you need to use an 82341 or 82350 HPIB (GPIB) card in the computer. I've also got leftover 82335 cards, and with a month may have extra 82341 cards. I don't know if software newer than A.06 is actually required to set up the 82341, and then dummy down to A.06 afterwards, but I think we did that once.
Also, if you use Windows 2000 or XP, apparently there are USB port GPIB adapters nowadays, have no idea what those cost. That might be a better way.
Also, remember that 1050 has been out of support a long time. However, they are darn good units barring autosampler drive and VWD optics major failure. Many of the pump parts are the same as 1100 and 1200 such as pistons, seals purge valves.
You might want to contact a third-party service and have them handle the whole start-up, and they also have spares that Agilent might not have for these. Alpha Omega Technologies, Full Spectrum, others come to mind.