Unplug the system and remove the battery.  Hold the power button for 30 seconds, and then remove and reinstall both memory modules.  If that doesn't solve the problem, try each memory module one at a time in each socket (one may be under the keyboard;  the other is under the memory cover at the bottom of the system) - until you isolate the bad module (replace it) or the bad socket (meaning a replacement mainboard is needed).

Hello TWilliamSofky,

The flashing Caps Lock LED indicates, Memory compatability error. Hence as Ejn63 suggested, please try one memory stick at a time, in each slot. Example: Take one memory stick, insert it into the first slot, and check if the computer boots to windows. Then try the same memory stick in second slot and follow the same pattern until you test both the memory sticks in both slots. This would help us isolate if the issue is with the memory stick or the memory slot (motherboard). 

Before performing the steps, read and follow the safety instructions in Dell Knowledge Base Article: "Precautionary Measures for Personal Safety". Remove all power sources including AC Adapter and Battery before you remove or re-install an item in your computer. For instructions on how to remove and replace the Memory Modules, please see the Service Manual: http://bit.ly/WKvMvU

Please write back with your findings. 

Many thanks to you and Dell-Allan D. I believe your suggestions have found my problem. The laptop will not begin to boot with either memory chip installed in only memory socket A under the keyboard. I used to regularly change parts in desktop units, but this is my first experience with a laptop.  I would like to repair this unit rather than purchase new as it has all updates for XP and other software.

A few more questions:

How difficult is it to change a laptop main board?  Have done several desktops, but no laptops. 

Should I try to obtain the exact same board, or get a newer, better main board?  If a different board, how can I be sure it will be compatible with the the rest of the system.

I apologize for taking so long to reply, but I have just returned home from knee replacement surgery. Thanks again. 

Hello TWilliamSofky,

As Ejn63 has said, replacing the motherboard means a complete tear down of the system. In case you are not comfortable replacing the motherboard yourself, you may ask for a technician while ordering the part from Dell Expired Warranty Services (at an extra cost).  

Thanks for your suggestion Allan-D. I am comfortable rebuilding unless soldering is involved, then I may have to rethink.  The main reason for wanting to repair is that this unit MUST operate with Windows XP in order to eliminate other problems. It is my understanding that XP can no longer be obtained.   This unit contains a lot of info that is not backed up. While it isn't imperative to retrieve it, I would prefer to.   I will check tht Dell expired warranty services site to check my options. I welcome any suggestions. Thanks. 

Hello TWilliamSofky,

Sure, please write back to us if you need any further assistance. 

I've repaired several Latitude laptops that had memory-slot issues without replacing the motherboard. In all cases, the metal-fingers in the memory-slot had gotten bent sideways out of alignment due to hasty memory installation. The solution was to use a tiny precision flat-tip screwdriver and bend the fingers back into the proper position. Then carefully re-inserting the memory straight down the slot restored laptop to proper operation.

Use a strong flashlight and magnifying glass to inspect both sides of the memory-slot.