I've got everything installed correctly, it's that, when I try to open the Arduino Application from the file arduino-1.0, it says "Could not find the main class: processing.app.Base. Program will exit." I got all the drivers on correctly (manually loaded them from arduino-1.0, complex)
Ok, so what we have here is an installation where the JVM (Java Virtual Machine -- the thing that actually provides the IDE) cannot find the main class (obvs, from the message). So, we haven't even exercised the drivers or anything yet. So let's put a pin in that part of the conversation.
So, this message means that the JVM could not find, or open or access lib/pde.jar in the arduinio-1.0 directory.
Assuming this file is there (is it? you should check) this is probably some sort of security thing. Have you tried right-clicking on the arduino-1.0/arduino.exe executable in Explorer and selecting "Run as administrator"?
Also, make sure you disable any real-time anti-virus programs. These can interfere with normal operation of any executable, resulting in weird results.
Once you have exhausted these options, I urge you to try to run the app from a new user account created just for this test, as sometimes there can be subtle user-specific issues that cause problems on Windows.