Lost DIMM socket 2 after multiple troubleshooting restarts

I have an MSI K8N Neo4 motherboard (NVIDIA nForce 4 Ultra/Standard Chipset)
I recently purchased and installed a Gigabyte 3D Galaxy II liquid cooling sytem in preparation for overclocking.  The cooling system has a built in shut off for overheating and low fluid levels.  When I plugged the control cable connector into the pump securely, the computer would boot for about 4-seconds, then turn off.  If I left the plug hang loosely, the computer would start and run fine.  The cooling system worked as expected.  However, it was easy to dislodge this plug and the computer would then turn off.  So, in the process of checking this Liquid Cooling System out, there were numerous restarts everywhere within the bootup process and after the box was fully up and running.  As  a result, I believe that some software became corrupted.  This was fixable by restoring a backup image I had made before I started this process.  

I finally removed the liquid cooling system and returned my computer to its air-cooled configuration.  However, after that, the computer would start up, emit one long beep several times, then shut down. One long beep is not covered in the Award BIOS beep code list.  By a process of elimination, I found that DIMM slot #2 was the culprit.  Any time I put a memory module therein, I got the long beep, refuse to start, shut down sequence.  In order to get the computer running, I had to vacate DIMM slots 2 and 4, thus removing a gigabyte of memory.

I also have noticed that when I go into the BIOS to make any changes, the f10 key (save and exit) no longer functions.  All other f-keys are working fine.

So, here are my questions:  
1.) Is there any way to restore DIMM slot 2 to working order?
2.)  Would flashing the BIOS be worthwhile?
3.)  Removing 1g of memory hasn't made any appreciable effect on how my computer works and the memory that remains is usually about 40-50% occupied.  Should I even worry about this?  I am not a gamer.