Take a look at the second drive and see if the jumper on the back is set properly. If your motherboard does not support cable select you will need to set the HD with the OS (the 20) to master. The second drive (the 40) will need to be set as slave.
There should be a diagram on the top of the drive to show you how to set the jumpers, and if not, go to the manufacturers site and see if you can find that information.
And if you are using a 40 wire cable the master needs to go on the middle connector. If you have an 80 wire cable the master/boot drive should go on the end of the cable.
i have Compaq p-III processor,
HDD-20GB of Quantum Fireball make..
OS-MS XP SP2
i would like to additionally add 40 GB HDD of Samsung make.
this HD has Windows 98 installed in it.
i tried to connect it but when both (20GB + 40GB) were connected then during booting it displayed
"OREATING SYSTEM NOT FOUND"
and when i connected the HDD individually then both were working properly..
is it the problem of non-compatible OS or smething else
i would want to use both the hard disk to increase my present config. of comp. to 60GB.
waiting for response.........and thanx