First Question is : Are you trying to set up a dual boot sytem or just run two HD's. If you are trying to dual boot, you'll have some work ahead of you. If your just adding a HD, you'll want to run one as a slave. We need more info to help.
I?ve a AMD III 450, 128MB and 32MB PCI graphic card, 200w power supply unit. A HD removable Rack for 6.4. OS windows 98se.
Is it possible to install another hard disk together with my 6.4 harddisk both with same OS (windows 98se) or different OS (one windows 95 and the other windows 98se) not using the removable HD rack!!
How to connect the cable with CD-ROM drive? how to set jumper to the 2 HD and the CD-ROM drive? and how to set the bios? Any problems with the power supply? How to boot up the OS?
Thanks for your help!

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