I have tried for two days to install various versions of OS 4.5, nothing. I have downloaded several OS's (and have uninstalled and rebooted before installing new), delete vendor.xml file, nothing. I have a T-Mobile 8100, have used Desktop Manager 4.5, 4.6 and 4.7 (uninstall, reboot, install new version, etc) and have performed all steps, including Vista's "Run as Administrator" - nothing.

The only OS that will work on the 8100 is the latest T-Mobile version from their website, regardless of what steps I take and what I do with the vendor.xml file. I have also tried the Loader application for the appLoader folder (Program Files/Common/Research in Motion/AppLoader), nothing. If I use JL_Cmder to wipe my 8100 and load that way (with deleting the vendor.xml file prior to plugging in my 8100), still get msg that device software is up to date, or that device software is not found.

I have been in IT for a long, long time - and nothing has been as frustrating as this. Any suggestions would be great!

Thanks!