how to open the maxtor personal storage 3200 enclosure / external case
some enclosures do not have slidable latches (see here)

You will need a long flat piece of metal.

On the sides of the enclosure are small slits.

If you look in the slits diagonally you will see a metal tab.

Slide the metal tabs about 1/4" towards the ends of the case.

The case will now open freely.