With you have 512 megs of memory your memory is in the configuration of 2x256 megs memory modules.
So the instructions would mean you remove one 256 module and try the system to see if it freezes with the one module. If not then remove that module and replace it with the other module and test the system.
I myself personally don't think it is a memory issue but the lack of memory you have.
I would skip part A and just download and burn the program as instructed and run it with both modules as it is now.