My Computer Restarts Whenever I Try To Sync It?

Hello, I have been experiencing a strange problem with my phone. Whenever I plug it in, my computer will recognize it, and BlackBerry Desktop Manager will open, and give me a menu of things that i can do. When i chose to manage media, it opens Roxio media manager for Blackberry, and allows me to do things like copy pictures on, and off of the device memory, as well as the card. Whenever i try to copy a file off of the device memory so I can put it on the memory card (I do this whenever the device memory begins to fill up) Windows explorer quits, and the computer shows the logging off screen, and reboots. I checked for updates, and that happens every time I do anything with the phone's internal memory. Any ideas?