The hard disk switch is labeled HDD POWER and is located on the back of the computer, next to the AC adapter socket:

Power switch

You can turn off the hard disk either before you turn on the computer or after:

If you do not plan to use the hard disk at all, turn it off before you turn on the computer.

If you need to load MS-DOS or an application program or to access files on the hard disk, leave the hard disk switch on when you turn on the computer, then turn it off later as described below.

4-18 Using the Equity LT-286