Beep codes

Amazingly, I had never heard of beep codes until yesterday.
But, when Margaret tried to boot up her Dell E520 Desktop, a series of beeps were heard, the monitor did not turn on and the machine totally failed to boot.
Tried a number of times with the very same result and the beeps always seemed to be in the same order so they weren't just random beeps.
However, I tried to boot again later that night and this time it did boot but stopped running when I tried a browser Edit>>Find command, the beeps sounded again and the machine shut down immediately.
I was really very worried and thought that the mother-board had died.
Then I googled around and found that these beeps were a BIOS message which could be interpreted to indicate what the error was. Here are some useful articles (first, second, third).
I saw somewhere else as well that a simple CMOS battery replacement may be enough to eliminate this problem.
The beep code I was getting seemed to be 1-3-2 however this doesn't show up in any of the tables I saw. The nearest was 1-3-1-1 which corresponds to a DRAM refresh error which can be rectified by reseating the DRAM sticks.
Indeed, looking at the table of Dell BIOS beep-codes it seems that all of these problems can be removed by a simple reseating of a memory or video card or a keyboard connector.
Our Dell E520 has two 512 MB RAM sticks which I just pushed in and indeed one seemed just a little out of place -- not much but perhaps enough to explain the problem.
I also replaced the CMOS battery (Lithium 2032) and then turned on the computer -- everything was normal after I did the setup.
Unfortunately, although I'm glad the problem was relatively minor I can't be sure whether the RAM reseat of the CMOS battery replacement fixed the problem.