i recently won Shining Force 1, 2 and Phantasy Star 4 off ebay and found that none of them holds any saved games after turning off the system power (this didnt surprise me, i was expecting this to happen cuz of the age of all genesis carts) so: 1 - is there a way to replace the cart batteries? 2 - do i need a special gamebit screwdriver to open the carts (i saw one on ebay for $20 US, i hope there are places cheaper then that)?? 3 - do the right batteries even exsist anymore??? 4 - if so where could i find a bunch of these batteries for sale (hopefully not extremely expensive either)???? 5 - is there a site with instructions on how to replace the battery or is it straight forward stuff with nothing complicated about it?????