If you think your hard drive is about to go to the great HD heaven in the sky (making funny noises, blue screen of death) then a clone may be the answer if you can get it to operate long enough. Cloning is also good for moving everything to a larger drive if you are out of space on your primary drive. Cloning used to be limited to desktops but now even the laptoppers are getting into cloning.
If done right, you can clone a drive, replace the existing drive with the clone and the machine never knows the difference. . Occasionally Microsoft will ask you to authenticate windows XP (different drive serial no.) but there is no problem, it authenticated itself over the net.
I am suggesting that this is a good way to back up a critical machine. Backing up data and saving images of your drives is a good thing. But there is no better way I think than cloning. I clone my main machine HD about every 3 months but since this works, I will probably do this once a month or so. I also use the external enclosure by copying other drive's data to a large drive for storage.
I had cloned a drive or two before using Clone-max, good program if you don't have multiple SATAs and IDEs on one machine, so it had it's limitations. I was running out of space on the primary drive C:. I needed to clone to a larger drive and of course back up the PC.
So I got
Acronis True Image Home 2010 that said it can even clone from USBs. I had already had a Manhattan external enclosure for an IDE drive that connected via USB. Guess what Acronis does clone to or from USB.
It accomplished it in about 2 hours (160gigs)
You will need the software, a drive as close to the one you are cloning as possible (but usually larger). This software allowus you to use USB but you can clone to a slave drive withing your computer..the drive jsut has to be as big or bigger.
http://www.manhattan-products.com/en-US/products/6735-drive-enclosurehttp://www.acronis.com/promo/ATIH2010/ (probably several other brands out there that wil do the same thing)
You gurus have already done all this, I'm sure.. just thought that if I can do it anyone can. You have to have a bit of mechanical knowledge of the insides of a computer, also.
If you put a new drive in the enclosure sometimes it needs to be initiated and formatted. Right click on [My Computer] click [Manage] then [Disk Management]