4gb but only 1.93gb usable

[rustless]

Hello
I have a little problem with my 4gb of ram :
I was using my computer and suddenly he restarded then my pc was so slow because I have only 1.93 gb usable
I also tried to untick the max memory size in the msconfig but nothing happens
can I get some help please
Thanks in advance
Ps: sorry for my bad english

 

[GhislainG]

You have one or two modules? If 2 modules, then one may be defective.