Let me be more specific. When I have UAC turned off, any command prompt or shell command that I open (a.) will be an elevated command prompt, and (b.) will respect the "START IN" location. The shell will execute with the desired folder as the current directory.
When I have UAC turned on, any command prompt or shell command that I execute, by default, will not be elevated. If I need to elevate it, I can, but in doing so, it stops respecting the "START IN" location and starts in C:\windows\system32.
In other words, if I leave it unelevated, the folder is correct but the command doesn't have the permissions it needs to accomplish the task, but if I elevate it, then it gets the permissions, but it's in the wrong folder.
If the thing I'm running is a batch file, I can fix this by adding this to the top of the batch file:
setlocal enableextensions
cd /d "%~dp0"
I've got no idea how the above works, but it does seem to work. I found it on the web after some searches. I don't know far back in windows versions it'll work. I know it works on Win7 and Vista but I'm not sure about XP for example.