How much RAM do you currently have? Try using Crucial's memory finder to see what the specs for add on memory would be. http://www.crucial.com/
Your MB is Ecs MCP61PM-AM, and the specs are here: http://www.ascendtech.us/ecs-mcp61pm-am-dual-core-am2-motherboard_i_mb64ecsmcp61pma.aspx
This would take 2 or 4 RAM sticks, and they should all be the same size. So, it would take 2, 4 or 8 GB of RAM, not 6 GB. Grab CPU-Z (you have an old version, v1.35, maybe 1.59 the log suggests both, and current is 1.52.2) and PCWizard from here: http://www.cpuid.com/
and that will tell you what is in your system right now, including RAM (sizes and timings). If you are unsure, just post a screen shot of CPU-Z (the Memory tab), and the Mainboard tab from PCWizard. Click on Physical Memory before getting the screenshot as that has the RAM specs. I'll find comparable for you if you want. RAM is very inexpensive these days, so it is a good time to stock up, and NewEgg always has specials for RAM going. I got 16GB of GSkill DDR3 (PC1600) for less than $70 recently. Note that Vista is a RAM hog, but 4 GB should be enough, and for W7 it is ample (see my W7 comment below), that might be a better way than upgrading RAM. 8 GB might be marginally better, but you won't notice all that much improvement, it will be very marginal over 4GB.
Depending on your needs, you might consider upgrading to W7. That is much more efficient than Vista - faster boot times, more stable, more responsive. And, 64 bit also, I'm pretty sure that board and CPU handle that as well. $100 at NewEgg but shop around, you can occasionally find it on sale. Windows Home http://www.newegg.com/Product/Product.aspx?Item=N82E16832116986
is what you would need.
I remember reading somewhere on the internet that the is a program that you can download that will uninstall all unnecessary stock programs (wildtangent games, trial software, ect.) all in one sweep. Have you heard anything about that? I think something like that would free up a lot of memory.
I think this is what you were thinking of: http://www.snapfiles.com/get/pcdecrap.html
for getting rid of junk. I've never used it myself, but it seems to be well reviewed. You might also check this out: http://www.snapfiles.com/get/soluto.html
it works pretty well. You can also grab WinPatrol, it has startup service and software controls.
The following startups are completely unnecessary, and you can kill them with either WinPatrol or Soluto:
uRun:  c:\users\asydre~1\appdata\local\temp\\jucheck.exe
mRun: [QuickTime Task] "c:\program files\quicktime\QTTask.exe" -atboottime
mRun: [SunJavaUpdateSched] "c:\program files\common files\java\java update\jusched.exe"
mRun: [Adobe ARM] "c:\program files\common files\adobe\arm\1.0\AdobeARM.exe"
mRun: [TkBellExe] "c:\program files\real\realplayer\update\realsched.exe" -osboot
cpuz135;cpuz135;c:\windows\system32\drivers\cpuz135_x32.sys [2011-12-13 21992] (outdated)
and you can also disable (don't delete!!!) the Windows Search service - I think it is a useless waste of CPU cycles, as well as the companion Indexer. Plus the AdobeARM service, that is also useless. This too is cute, but unnecessary: c:\program files\stardock\object desktop\deskscapes3\deskscapes.dll
I would uninstall:
Game Console - WildGames
HijackThis 2.0.2 (outdated)
Pando Media Booster
Pepsky Free Mp3 CD Maker 188.8.131.526 (depending on where it was downloaded from - trusted sources only)
Now the Dxdiag log I will have to attack because the site says that it forbids me to post due to a "possible trojan attack or infection". It's happened before but I don't know why.
That's a bug in our anti-spammer filters which we are attempting to hunt down. Unless there were errors in the log, I don't need to see it. If there were errors and I need to review the log, zip the log and attach that. That will bypass that filter.
I did not see any evidence of potential malware on the system in the DDS log.
I think that pretty well covers what I saw in the DDS logs and your questions.