This item is from the Yet Another Enhanced IDE/Fast-ATA/ATA-2 FAQ, by John Wehman and Peter den Haan with numerous contributions by others. (v1.92).
If you have a Triton II or Natoma based board, the retail version of Win95 may not recognize the PIIX3 interface. This will trigger an entertaining bit of Plug'n'Pray magic which eventually causes the BIOS to disable the secondary IDE channel on the next reboot.
To determine if this is really your problem, go into the device manager and click on Hard Disk Controllers. If you see the following devices listed:
o Primary IDE Controller (single FIFO)
o Standard Dual PCI IDE Controller
o Standard IDEESDI Hard Disk Controller/
your Win95 mshdc.inf needs a little update. You can download this from <ftp://ftp.intel.com/pub/patch/>.