I had the same problem with nokia 3110c and a 1gb minisd card and restarting after logo startup and I solved the problem with formatting the minisd card on the computer not in a phone but If it`s not working full flash the phone and factory settings ... Finally if it`s not working it`s hardware problem. Good luck.

Try formatting the 2GB card on the phone. Also, if the card you are using is a MicroSD HC, from what I found, won't work in the 3120.

u must also try google search for this solution..........!

I inserted 1GB MicroSD card to my Nokia 3120 classic.
After some times, when I restart the phone without this memory card or with another memory card, the phone crash. It shows blinking white screen for seconds, and then turn off.
But,if i insert the memory card,the turn on sucessfully.
What should I do? I want to use my new 2GB memory card... But,it always crash...
I also already tried 'reset to factory default'. It solved the problem at that time. But in next 2 or 3 weeks, this problem reocured. Any solutions, Help me please....