Have you rebooted both the Storm and your computer? I would do that for sure before trying anything else.
Also, it sounds odd, but try taking out the battery out of your Storm, plug it in to you computer with the battery still out and see if DM or the Loader.exe recognizes it then. This does work sometimes. Then, when you start going through the precess of whatever it is you want to do, put the battery back in to the phone.
Try unplugging the phone, removing the battery, inserting the battery, and in those few seconds that the red light on the front is on, plug the USB cable back in. Be quick, you only have like 2-4 seconds. Then wait for the phone to boot up, see if that works.
If none of the above works try this, with your BB plugged in open your PC's device manager and look for your BB under the USB devices and if its there right click on it and select update drivers.
Posted from my CrackBerry at wapforums.crackberry.com
Doesn't matter. Try it. Like I said, my old ipod would ONLY work on one particular port, but the port was fine for every other peripheral I plugged in there. What do you have to lose?
umm have you changed the setting in your phone to the following
go t to memory and put everything to yes under all the options. leave encryption mode to none! that should work!
don't take it personal I just like the animation 
