OLD SONY SOFTWARE TO NEW COMPUTER

I've just had to get a new computer and my Sony eReader PRS 505 software won't load. Sony say that the software is just too old.
This is annoying because the reader works perfectly well (I don't buy a lot of new books anyway) but it looks like I'll have to replace it anyway.
UNLESS..... does anybody know of any tricks that might work to fool either the computer or the reader?
thanks