[ayato]

If you have the .cab file on your computer, connect your phone via usb activesync. Once connected, you can click on the explore button on activesync (For windows XP) which lets you look at the files and folders on your phone. Copy that .cab file you have to anywhere you want on the phone. I usually put it in the My Documents folder. Once copied to your phone. Go to the file explorer program on your phone and get to that file. Then you just click on it. The .cab file knows what to do on your phone. Simply click it and it will step you through the rest.