Computer freeze when external HD is turned on
First of all I'm an Asian and I'm sorry because I have a bad english.
Okay.. I have a Sony Vaio PCV-RZ24G.. I have only 1 external enclosure HDD Sata.. and I have 3 sata HDD internal - 1Tb Seagate, 500Gb Hitachi, and 250gb Maxtor.. I'm using these HD for a year with no problem. I just need to insert the HD that I want to access to the enclosure and turn it on and I have no problem doing this (im doing this, while the PC is turned on)..
Now here's the problem.. it's been a month.. when the computer is turned on, and plug in the usb-enclosure, my PC freezes so I'm going to have to force turn off my PC, and when I restarted my PC, the HD that I just inserted is on my computer, and my PC works perfectly..
Its just annoying that whenever I plug in any of my HD while the computer is turned on, my computer always freezes.. but when I plug in my HD while the computer is turned off, and then turn it on, there is no problem..
Please help.. there's a lot of important files with these 3 HD.. please help..