Hopefully someone can help with this problem. I have an external USB hard drive to back up documents and photos, but now the PC refuses to boot if the device is connected. This is a recent problem despite using the same hard drive for some time...it's as if the PC is trying to boot from the external drive which of course doesn't contain the relevant files. As soon as the Windows start up process has begun then it can be connected again. Is this something to do with the Windows boot configuration, if so how do I change it? If it's relevant my operating system is Vista Home Premium SP1.