out of memory error

Hello. I have a problem.

I could solve my program using my computer.

But I can't solve my program after I did format my computer.

All hardware and software are same.

I received error message "Out of memory during assembly".

So I reduced mesh. But I received error message "Out of memory during LU"

I reduced mesh again.

I can solve my program but it is not same answer before format my computer.

First mesh size was 4nm. but recently smallest mesh size is 400nm.

What can I do? Please help me.