Unlike many who have had this problem, I don't think this a PC driver issue. My Vibrant suddenly will not mount. I have it set to MASS STORAGE as it always has been, and now it usually won't bring up the USB notification (about 50/50 on this) on the phone and I get a USB Device not recognized error in Windows XP and Windows 7. The phone is NOT rooted. I flashed JI2 with ODIN. I know it worked after that because I copied back my music movies and games back to the Vibrant from pc's running XP and 7. Also, as a control, my coworkers Vibrant has no problem being recognized by my PC or his (mine does not work on either). Also, not sure if it does this normal, but when I plug it into my wall charger it brings up the notification to mount. I have exhausted most of my options (drivers, kies, master resets etc..) I can get into download mode, but Odin does not see the phone (I though reflashing might fix it). I have a replacement on the way, but I hate to swap it out since JI2 appears to have fixed the GPS issue for me and i'm afraid of getting a locked replacement. Any ideas?