You can use Bluetooth to transfer video to your HTC Desire Z .
Open your pc then click start > all programs > accesories > communication > bluetooth file transfer wizard. Make sure you has plugged the device in your USB hub and also make sure you turn on bluetooth in your mobile phone.
You can use the data cable to transfer video to your HTC Desire Z.
If you need to connect your computer to transfer videos, we recommend you to the official website to download the Samsung USB drivers “samsung kies”.
Download Page: http://www.samsung.com/cn/support/usefulsoftware/KIES/JSP
When the software installed on your computer, then cancel HTC Desire Z USB debugging (go to settings – applications – development-USB debugging), then connect the data cable.
1 Set – More-USB Application – attached storage to a computer (not connected to the case click) – Connect a USB cable to use mass storage (do not click on this dialog box to cancel) – Connect USB cable – HTC Desire Z will prompt open the USB storage device to play – click
2 Select the appropriate folder, copy the videos to HTC Desire Z folder.