I wont suggest you to change the default path, But I will give you smart solution to do it. only thing you will have to do is to run a simple command and it will go to the location where you wanted to go. Do the following to accomplish this
open the default path in windows explorer open notepad and write cd save this file named somename.bat and as all files (NOT TXT). then whenever you open command prompt write this somename you given and you will be at your desired location.
if you have problem in installing gmail voice and video chat program it stucks in detecting devices... then you just start "run" in windows OS and type in "%USERPROFILE%\Local Settings\Application Data\Google\Google Talk Plugin" press enter you will see a window opens up. In this window just delete the file "googletalkplugin_port" and re open gmail.