Computer startup problems

I all,
I have a problem on my Windows Vista that began afetr the purchase of an external Hard Disk Freecom.
A few days afetr the purchase I disconnected it while it was writing and, since that moment, every time I connect and disconnect it, the PC go to freeze mode for 5 minutes.
The same thing happen even if the hard disk is disconnected: every time I start windows it go to freeze a little after the password, and every time I connect and disconnect a usb device.
I have looked for the solution everywhere, updated windows, unistalled and installed the hard disk from the device manager but I solved the problem only when I restored a recent backup.
Yesterday the Hard disk was writing a backup while Vista was installing the updates; at the end of the proceure windows restarted automatically and the problem began again!!!
The Pc go to freeze when it starts, every time I connect or disconnect the hard disk, an usb earphone that has always worked switch on but there is no audio and I don't know how many others usb devices will have problems.
Has anyone an idea to solve this problem before I throw out of the window Vista or the the hard disk?
Thank you


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