i have a T20, which is no doubt old by any standards, but i like it very much.The internal hard disk(4 GB) is out of order.I removed the internal HD & tried using a USB extarnal hard disk ( 160GB of WD make).
The following are the steps followed by me, But it din't work:
1.remove internal hard disk
2.Start the lap top ,with windows XP OS in the CD drive.
3.go to bios setting
4.make the bootable device as CD drive.
5.Connect the USB hard disk
6.Follow the steps to load the OS in the external hard disk.

At one point the screen message says" you need specific software to install the OS in the USB drive'

Can some one help me.
From
Ramgopal.

If the external hard disk is 2.5" and PATA (but not SATA), take it out of its enclosure and mount it inside the T20, using the caddy and screws from the old 4GB.
You cannot load an OS via an internal CD onto an external HD.

I have heard about bootable USB .
So thats what i tried.
Is there any way ,i can still try.

http://www.ngine.de/article/id/8

It can be done on a laptop that is capable of booting from USB. I have no idea if a T20 is capable of that.

Thanks for the reply.
Can any one tell me ,what needs to be done ,to make T20 suitable for booting from USB.

My next option is to buy a compatible hard disk to replace the existing one ( IBM travel star).Can you suggest any brand ,model( SATA or PATA),memory size etc.

Google is your friend. It says at the follow link that USB hard drive booting is not supported on a T20.
http://www.thinkwiki.org/wiki/Supported_Boot_Devices

You need a 9.5mm high, 2.5" wide laptop IDE (also known as ATA-6) drive. There is no limit on size except for the fact that 320GB is the largest currently available.

Thanks for quick reply.
I shall now look for suitable HD