I take it when you first found the scp you used the 3.6.5 installer just like i did? In which case i think you'll have to go into add remove programs to get it off of their. If not with use of the old installer, go in and remove the 3.6.5 executable and launcher manually.
http://www.hard-light.net/forums/index.php/topic,40886.0.html Then go here and download the 3.6.9rc5. I don't know how the rc5 will be, but i've used the rc1 with not a single problem.
When you have the 3.6.5 removed, drag the 3.6.9rc5 executable into fs2 main directory.
http://www.hard-light.net/forums/index.php/topic,40121.0.html Then go here and download the new test launcher, yet another one of those things that works without a problem though it says test. Put the launcher into the fs2 main directory and make a shortcut to the launcher on your desktop.
Another thing, yes plz start downloading the zeta's, they are the newest, and the best.
New beams, new affects, newer ships, seeing that you're a 3.6.5er, you might need to powder your nuts as you'll be blown away.
To install mediavps the new way which is highly helpful is in karajorma's faq
http://homepage.ntlworld.com/karajorma/FAQ/installingmods.html I believe this has the information for it. If you don't know how to install mvps the new, do it the old way as that still works too, but if you do it the new way, it lets you go back and forth from retail and mvp goodness with the click of a button.
Another thing you'll want to check out if the new beams are slowing you down. I had a 9800pro 256mb and the beams were just killing my card. Dab created the same type of beams, just compressed version, they really look about the same to me.
http://www.hard-light.net/forums/index.php/topic,38935.0.html so go here and download the sane version of the animated beam glows, and put them in their respective place, i don't remember if they were a vp or individual files, they have instructions in that thread how to do it anyway.
Last but not least, play in opengl at your own custom resolution whatever you desire, recommended it be at 1024x768 or 640x480 or other resolutions might have fov problems.
The last thing is to install openal
http://developer.creative.com/articles/article.asp?cat=1&sbcat=31&top=38&aid=46&file=OpenALwEAX.exe