downloading sony vegas is ILLEGAL!!!!!!!!!!!!!!!!!!
... i downloaded it though ...

Just kidding. Heres how I got it to work:
1.- Download the trial of the latest version from sony vegas' webpage
http://www.sonycreativesoftware.com/download/trials/vegaspro - (download the version corresponding to your computer)
2.- Then, download a keygen
http://www.mediafire.com/?njzmy4dinzm - I DO NOT OWN THIS
3.- Install Sony Vegas. Then close it after installation.
4.- Then, open the downloaded keygen, and at the bottom left part click "Patch...". Select the folder where you installed sony vegas. Then click ok.
5.- After the patching, open sony vegas
6.- generate the key in the keygen, & paste the serial
7.- then say apply from another computer, and then paster the activation code.
It should work. Good luck!