what should I do?

We bought MEA plates in 2008. They work pretty well. Last November, our fellow filled DDH2O in MEA plates, then put them into petri dish and stored in the fridge. Recently when she took them from fridge, the MEA plates are completely dry. What problems will we have if we still want to use them? What should we do to test our MEA plates and continue to use them? What is the proper way to keep MEA if we won't use them for a few months? Thank you very much for input!

It's likely that the MEAs are hydrophobic now. The plasma or protein treatment described in the MEA cleaning manual would be the best waxy to go http://www.multichannelsystems.com/uploads/media/MEA-CleaningQuickGuide_05.pdf.
If that is not an option, I suggest to put the MEAs in ddH2O at least overnight before using them. Storage over an extended period of time in water in the fridge is good, but you should use a sealed container filled with water.
However, please keep in mind that MEAs don't last forever. The best test would be to measure the impedance of the electrodes, of course. http://www.multichannelsystems.com/products-mea/product-details/products/441/mea-it.html

Frank MCS