Fingers crossed we might be able to track down the cause of the problem by interrogating minidumps of the blue screens with Windows debugging tools.
So first we'd better check to see if your PC has been collecting minidumps of the crash.
Open My Computer, and see if you can find a directory called C:\Windows\Minidump. (That's where minidumps usually go on a PC, so long as the Systemroot hasn't been set to some other folder.)
If it's been collecting minidumps, there should be files in there with names like "Mini(number-numbers).dmp" or just "(numbers-numbers).dmp".
(If you have "Hide filename extensions for known file types" enabled on the PC, the ".dmp" extension may not appear on the dump files. The numbers in the file name will be different for each minidump, if minidumps are present.)
Are there any minidumps about on the PC? If so, we'll go digging in them.
1. Download and install the Windows debugging tools from here:
http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx
2. Go "Start > All Programs > Debugging Tools For Windows > Windbg". Once you open Windbg, you will presented with a blank screen.
3. Click on "File > Symbol File Path". Here you will enter the symbols path. Symbols are needed to effectively debug.The path will be:
SRV*c:\symbols*http://msdl.microsoft.com/download/symbols
4. Enter in this path and click OK. Now, go to "File > Save Workspace" so that your symbols path is saved for future use.
5. Go to "File > Open Crash Dump" and load the file.
(An "Open Crash Dump" screen will appear ... doubleclick "My Computer", doubleclick "Local Disk", doubleclick "Windows", doubleclick "Minidump", and doubleclick on one of the minidumps in there that was generated at the same time as the Classic was plugged in.)
You will/should get a message to save base workspace information. Choose no.
Now you will get a debugging screen. It takes a little bit to run it, as the symbols have to be downloaded as they are needed.
After the "bugcheck analysis" part of the screen comes up, look for the component that seems to be causing the crash. (It'll say "Probably caused by" ...)
Let us know the precise name of the component. (Include any file name extensions like .dll or .sys.)
If you can, have a look at several of your crash dumps generated by USB-pluggings-in. Are all the crashes being caused by the same component? If not, could you let us know the names of the various components being cited in the various crash dumps?
