Try here first: http://www.kb.sony.com/selfservice/microsites/search.do?cmd=displayKC&externalId=C354794&fes=true&mdl=DSCW350
Formats the memory card or the internal memory. When you use a memory card with this
camera for the first time, it is recommended to format the card using the camera for stable
performance of the memory card before shooting. Note that formatting permanently erases all
data on the memory card, and is unrecoverable. Save precious data on a computer, etc.
(Memory Card Tool)
Circle (?) on the Control Button
Page 97: http://www.docs.sony.com/release/DSCW350_handbook.pdf