Dell e520 bios setup

[Guest]

I have a Dell E520 desktop. I tried to upgrade the memory. It has 4 slots and 2 have 512 MB chips; I have 2 identical chips. The BIOS does not recognize them, and it says that memory and CPU, etc., are "unchangeable". But the owners manual says it is upgradeable to 4 GB (4 1 GB chips). Why, and how can I get around it to use the 2 new chips. Memory is in slots 1 and 3 and is recognized. Memory in slots 2 and 4 is not, but it is the BIOS I think.

 

[Gulli]

Are you saying memory in slots 1 and 3 is recognized? If so, what's the problem?

 

[delluser1]

Never saw a bios say that memory and cpu were unchangeable.
Have you tried swapping slots ?
What are the specs of the memory ? ( Both existing and upgrade chips )