use this program: http://sourceforge.net/projects/win32diskimager/
I downloaded that program and the Bitmain.img file in the quotes but My win32 disk Imager program doesn't offer any option to format. I can format in windows explorer under fat32 I used "Default Unit Size" as Allocation unit size optionquick format checked. I tried to do this to one miner and it worked! Only after i bought a new micro sd card, I think re-writing the micro sd a bunch of times corrupted it. I'll try the same on the other two now.
OK Update.. Good news all 3 1TH/s miners are hashing, the problem was with the Micro SD cards. 3 new Verbatim 8gb cards & it works.
My S2 also went down last night, it suddenly started beeping like crazy after dropping to 800GH/s when my S1 had no problems. I ejected the card, switched it off, reinserted the card and it started up and carried on as normal, although I find it hashes more often below 1TH/s than above
