hello.
i have a problem with one of my hard disks and windows. actually, my windows got corrupted and i decided to reinstall it. i formatted my second 40 GB hard drive and installed windows in it, thinking of later formatting the drive with the corrupted windows which was on the other 80 GB drive. but now when i try to run the computer with both the drives connected and with the new windows drive as my 1st boot device, the computer gives "error 115" and directs me to BIOS setup. i get the same messege when i try to run with only the 80 GB drive connected.
so i thought of formatting the drive partition with the old windows using the windows CD, but when i run the windows CD, it gets stuck whenever it tries to read or examine the 80 Gb hard drive. also, the 80 GB hard disk has data which i really want to save on a seperate partition.
hope you understand my problem. Please help with it and give some possible solution. please.
thanks 

Have you made sure that the 40GB HDD is in th primary position and not the slave?  You might just need to change the cable inside the box to have the correct oder inside there.  I hope this works for you, I hope even more that I understood you correctly

EDIT: I did confirm with a quick google search that windows can only be installed on the primary partition of the primary drive, you just have to make sure that cable has the HDDs in the correct order.

Unplug the 80Gb drive the first time you boot, just to make sure that you CAN boot it to windows ok. If this passes, make sure that the 40Gb drive is on the end of the IDE cable, and set the jumper switch near the cable plug to master or cable select. the first two pictures on THIS site will give an idea of where this jumper is.

Connect the 80 Gb drive to the middle of the IDE cable, setting its jumper to slave or cable select.

thanks for the replies guys.
ok, i will check the jumpers and try again. the computer starts if i use only the 40 GB drive.
also, the 40 GB is a ATA (samsung) while the 80 GB one is a SATA drive(seagate).