This is a very old unit and HP does not have the recovery discs for them.
I checked online and found this link where they do sell recovery discs for your unit.
http://www.restoredisks.com/manufactures/Hewlettpackard.aspx
I do now know the authenticity of the website and how they work. Since you wanted to get the recovery discs, I'm sharing this information.
Hope this helps.
DO NOT HOLD HP RESPONSIBLE OR ME FOR ANY FAILURES/ISSUES.