i have a microsd card strongnium 2GB which is shown 45MB.

Is there any formatting tool for regaining full 2GB?

hmm, another one. There seems to be quite a few MicroSD showing low capacity. Generally there is no fix. A DR outfit may be able to read the NAND inside to recover data, but even that is iffy.

I don't think you can regain capacity, all the ones I have seen have been written off. There is another thread with a card showing 31MB, maybe have a look at that as well for more.