I have a Silvia thats been sitting for about three years unused. I feel bad enough about it already, but I probably deserve whatever flaming comes my way. Anyway, I read through all the FAQs on cleaning (which are great, btw), but would like to know if there is anything else I need to do to the machine to prepare it for use after three years other than a thorough cleaning. Thank you in advance.

Assuming the grouphead gasket isn't dried out, the same procedure you'd do for descaling should suffice. See Advice about bringing an espresso machine out of storage? and How do I descale my espresso machine? from the FAQs for more details.