Installing Linux on External HDD

Hi,
I want to install LINUX on my laptop. I have a 2GHZ,1GB RAM and HDD is not partitioned. I donot want to touch this HDD and I have external HDD of 200GB. Can I install LINUX on this external HDD?. I would like system to detect linux only when I connect my external hard drive. else system should continue to boot with default winXp. Is there any way to achieve this?

Thanks
Suresh

It depends on your system. If you can set the boot order in the CMOS settings to try booting from USB before your hard drive, it'll do what you want.

Hi,
Thanks for your help.
Do you suggest any other way than setting it in CMOS?

Thanks
Suresh

The CMOS is the very thing that determines what device your system boots from. There's nothing below it to fiddle with, and anything above it by definition would have to be booted first. If the CMOS won't support it, nothing will.

With a system that modern, it'd be suprising if the CMOS didn't support USB boot devices, though.

Maybe you need some hard device.In china market,there is a harddisk switch,it can do it.
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Hard to install that in a laptop.