I have three questions. My husband obtained an old computer out of the trash at his workplace. It had a relatively newer hard drive in it (Caviar 22100). I need to replace his mothers hard drive and I hope to use it. My questions are, first: Can I format this hard drive in my pc as a slave hard drive or do I need to replace it as the master? Second: After formating can I install Win98 even if it had some other software previously installed? Third: Can I install the Win98 on this hard drive while it is in my pc even if I already have win98 on my hard drive? This is the first time I have ever done this and I appologize if I sound really stupid.

Not stupid at all. Very good questions. Of course I had to read it twice to understand fully what you are doing lol.

First q: yes you can format it as a slave. you have to make SURE the one you format is the correct one. It will more than likley be your d:\ drive. a good way to check what drive your looking at in DOS is to Type the command "DIR" this will give you a directory listing of the drive. from that listing you should be able to determine if you are formating the right one or not.

Second q: after a format, you can install anything you want. the computer will have no clue what was there before.

Third Q: yes you can install Win98 on it althouhg win98 is already there. Once again. make sure you know what drive letter it is (prob d:) and just change the install path when installing windows.

yes,yes,& I wouldn't.
Move the hdd jumper to slave.
Boot & watch to see if it detects it, if not you'll need to enter cmos & configure it to auto detect, save & exit.
(Cmos setup utility is launched by the F1,F2 or del key.)
Once you boot into windows & the drive is assigned a letter, simply format it in Windows. Use thorough, & don't worry about the popup nag screen warning.
Copy the Win98 & Driver Folders plus the Tools folder if want to use any ot the utilities, if not don't bother.
Then copy the setup.exe prog.
You can then test it by launching setup in windows to see if the initial install procedures work, then exit setup.
Make a startup disk & do a test boot with it.
@ the A:\ prompt type: D:\ assuming that is the current drive letter assigned to the caviar. Then type: setup & it should launch.
Close the setup whenever you like & shutdown.
Note: The reason I wouldn't install 98 on your computer is due to the hardware & drivers being different from your Moms computer.(I assume, that is.)
Set the jumper to master & install the hdd in your Moms comp. Make sure the red wires of the ribbon & power cables are facing each other.
Insert the bootdisk & bootup, if the bios doesn't recognize the hdd during post then repeat the procedure above, as well as for launching setup.exe for the install.

BASICS: http:// www.techtony.com
http://www.compguystechweb.com/index.html
http://support.microsoft.com/support/kb/articles/Q255/8/67.ASP
http://homepage.ntlworld.com/robert.bale/index1.html
http://www.geekmaster.50megs.com/index.html