OK my old Tivo 240080 quit recording live tv. Everything else works fine. I have been transferring shows to it from the computer to watch for a while. Came across a deal on ebay. Model 540040, It was supposedly working when it left the seller. Now it is stuck on powering up. It has a WK add on kit, Twin breeze, power trip, the whole 9 yards. the original is a 40 gig maxtor and the add on is a maxtor 140 gig. The fan on the bracket is on the far side of the drives instead of between them like in the photo on the website. It seems like the second hard drive is not powering up but it is hard to tell as the extra fan is kicking on at 7 seconds also. The second hard drive does NOT warm up like the first one though.
About a year ago I replaced the hard drive in my 240080 with an upgrade from WK. Can I take the hard drive from it and put it in the 540040?
I guess my question is, is the software between these two models compatible?

Any other way to make a good setup with these two tivos.
My plan was to use the new-to-me tivo in the living room and us my old one (has a lifetime subscription) in my daughters room and transfer her shows to it. But I really need to have at least one working tivo.