I have the same problem...
I have just bought a 4GB SanDisk memory card for my samsung.
I bought it from play.com and it doesn't seem to be working so well.
On my phone it says that the memory card is inserted but when i go into the files and click on memory status- memory card, it reloads my phone and nothing happens. When i click on the memory card itself a message comes up saying 'unrecognised. format?' i press yes and it says failed every single time.

I want to know how to format it and why it isn't working. Some people say it is damaged but i have just bought it so it cant be!!
I thought i might have been able to do it by putting the memory card in my phone and conecting it to the computer and somehow formatting it then but it still wont show up on my computer. It has come with an adapter and i would also like to know how you just put the memory card into the computer.
This would really help because i was really looking forward to putting more songs and photos and videos onto my phone so i got a memory card and it doesn't work! So please say someone can help me

xx
Sibbii
Thankuu x