Sam Nickaby wrote:
We have these PVC sliding windows that have locks that press
in until it clicks before you can slide them open. When you want shut
the window, you just slide the window shut and the window will
lock automatically.

The problem is that these are badly designed locks. I didn't know
about this problem until my neighbor with the same window got
broken in. They now use a lengthy wooden rod to lock the
window. They said the bad guys used a credit card to open
the lock. What is a practical way to protect these windows
from thieves?

What your neighbor did. It's the simplest, surest way and doesn't
require window modifications. Paint the stick white and you'll never
notice it.

R