Windows vista startup problem

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

Use a restore point and blacklist that update.

Run the Vista DVD. Tell it you want to install Vista. When it finds the Vista partition, tell it you want to repair Vista, not delete it. That will knock out most of your M$ updates. You can try to create a restore point and update again to get all your updates back. After that, defragment and fix hard drive errors with the auto-repair option enabled.

(It's in the Computer section and you right click on the hard drive partition which has Vista, XP or whatever.)