I have just bought a new microSD card for my Sony Xperia, with Android, as it had no memory left.
The phone doesn’t seem to be recognizing the memory card and it’s still saying no memory left. What do I do?
There are two issues here. First of all, "out of memory" usually refers to RAM (random access memory), not to storage memory, which is what the card is. To find out how much your phone is using and how much memory is still available, open Settings, then touch Manage Applications, Running and read the figures at the bottom of the screen.
Secondly, with regard to storage space, Android saves all the data in the internal memory. To make use of the card, you either need to explicitly save things there or to move data or apps to the card using a 3rd party app.
may be the sd card is not compatible, check with another one.
do format to FAT32