GG
I'm assuming that you simply deleted the hubs in device manager and then refound them....if so that shouldn't cause issues.
However can you just confirm one thing - you formatted ONE pen drive, and now BOTH are giving you problems? Or were both reformatted?
scotbill
Are you sure the machine was actually stalling, or simply not visually responding while copying files? Its common for a large file copy over USB to apparently stall a machine while the files are actually moved. Especially true of Vista, but other versions of windows do it also
The machine will usually come back to life after the transfer is complete