OS and Hardware Instability, please help

Question

Hello - I've read through a lot on these boards and I don't quite see an answer to My problem.  You folks seem helpful though, so I'm going to put Myself into your hands for assistance.
Last Friday My PC shut down out of nowhere, and wouldn't bring the OS back up.  After checking a lot of things I figured out that one of My 3 memory chips got fried somehow.  You don't just see this happen very often...but I guess it does.  So, I went with the other 2 (still leaving Me with 1GB memory) and tried to keep on going.
Once back in Windows I started getting software errors - where it says "please send this report into Microsoft".  It happened mostly with two things - My main game (City of Heroes - online game) and IE.  Seemingly at random times.  Once in a while the PC would also just simply reboot itself out of nowhere.  I figured the OS got hurt when the memory chip blew up, and couldn't "fix" the OS no matter what I did.  
So, I decided to download XP 64 Beta.  Big Mistake.  Not only did it take forever to get the drivers loaded, software running, etc - but I also ended up with the EXACT same problems.  This was after Fdisking My hard drive and everything.  So I got rid of XP64 and put XP back on.  Yep...still same problems all around.
I've disconnected everything from the board (processor included) and reseeded it all.  I've checked to make sure there are no loose wires, that the power cable has no crimps or frays, and that it is plugged securely into the surge protector (which in turn is plugged into a very good UPS).
Fresh build on an Fdisked drive, latest drivers for everything including all the MB stuff from MSI Live Update (BIOS as well).   I simply don't know what to check any more, or what else to do without assuming that the MB is fried, and that likely being the reason why the memory blew up and the PC hard crashes now and then as well.
Also important to note:  The PC ran fine for almost 3 months (when I first put it together), until now.  I have not installed any additional hardware or software lately that would have caused any changes that I know of.
Here's My system specs, please let Me know if I left anything out.  If there's anything else I should check please let Me know, I'd greatly appreciate it.
-Drake
MSI K8T Neo-FSR (red board with VIA chipset, even though the product page here lists the FSR as an NVidia with blue board??)
AMD Athlon 64 3200+
1GB (left) of Kingston 512MB DDR400 Dimms, in slots 1 and 2
ATI Radeon 9800 XT 256MB (latest 4.6 Catalyst drivers)
Creative SB Live! 5.1 Sound Card in slot 5 (leaving plenty of room for air flow to the video card's fan)
Windows XP SP1 (all critical and non-critical updates applied)

Answer 1

Again, thanks for the responses!  It's been helpful.
Right now I'm running with only one DIMM and it's not crashing.  I was able to play My game last night for about 2 hours without crashing, which is a first in a while.  
Now, I would of course rather run with 2 of these chips instead of just the 1, but I'm a little confused about what was said above.  
I downloaded CPU-Z and I'm checking out the memory information.  First off, it says My Frequency is 200.0 MHz...shouldn't this read 400?  That's what I have it set at in the Bios.  Here's what it says there for Memory:
Size 512 MBytes
Channels # Single
DIMM#1 Kingston DDR-SDRAM PC3200 512 MB
Timings:
Frequency 200.0 MHz
FSB:DRAM CPU/10
CAS# Latency 2.5 clocks
RAS# to CAS# Delay 3 clocks
RAS# Precharge 3 clocks
Cycle Time (Tras) 8 clocks
Bank Cycle Time (Trc) 11 clocks
DRAM Idle Timer 16 clocks
(Total CAS# and Row To Column are grayed out)
I'm not sure what you meant by "3-3-3-" and "4-4-4".  I don't see anything like that on CPU-Z, nor do I recall anything like that in the bios, but I'll check it.  If you mean the frequency (as in 333/400) like I said above I do have that set to 400 but it's reporting in CPU-Z as 200.
DeMaxx - I'll try the #1 and #3 thing to see if that helps, but I know with 2 DIMMS in #1 and #2 I was still getting errors.  I'll test now.
Thanks again, I'll keep trying!
-Drake