Since you changed memory and it still showed the same memory that more or less points to the memory slot rather than the memory, assuming you have the correct memory type for this model. 

However, Dell's have a history of compatibility with some brands of memory (and a certain brand can work in one and not another of the same model).  For this reason we recommend Crucial Memory for non-Dell memory as it is guaranteed to work with Dell's.

Did you try the Dell diagnostics that are (or were) on the hard drive, accessed by F12 at Power On.

HERE is the Crucial listing.  Note that it requires 1.8 Volt memory.

Hi adavisclan,

Welcome to the Community,

If the same memory module is working on DIM 1  and not working on DIMM 2,its not a problem with the memory module.Its a problem with the DIMM 2 slot.

Try using the system without any memory module on DIMM 2 and see if it works normally.

Thank You

Hello Roshan,

Thanks so much for your suggestion.  I removed the memory module from DIMM_2  as you suggested, and the computer seems to be working now.  That leaves me with another problem.  If the DiMM_2 slot is the problem, is there a fix for that? Since I'm running Windows 7 along with many other programs I need all the memory I can get (i.e. all four slots). Would appreciate any suggestion you could offer.

Thanks again for your help in identifying the culprit.

ADavisClan

The memory modules in DIMM_1 and_2 are the orinal Samsungs which came with the computer.

Hi adavisclan,

To fix the DIMM_2 slot the motherboard needs to be replaced.The other option would be to buy two 2 GB memory module  and use it in DIM_3 and DIM_4 and let go of the 1 GB memory  modules you've on the system.This way your system will have a total of 4 GB RAM (which is the maximum your system can support).

Note:To take advantage of the system's dual-channel memory bus, a pair of matched memory modules need to be installed in one or more channels. If the pairs are not matched, the system memory bus operates in single-channel mode.So for this reason you should not be using the 1GB memory module which are there on the system.

Use the link below to find a pair of compatible 2 GB memory module:

lt.dell.com/.../lt.aspx

Let me know if you have any further query.

Thank You