Protecting programs from being erased or overwritten

I just did a search on this forum, so forgive me if it's already been answered, but I had no luck with the search engine.

Title is self-explanatory.
Short version is I had a couple programs overwritten last week by another guy and until I can safely download them, I'd like to prevent that from happening.
I'm pretty sure there's a way, but didn't find it in the manuals.
We have a vf-3,5 and 10.
The 3 and 10 are probably 5-10 years old and the vf-5 is about a year old, so fairly recent controls.
Is there a way to do it individually or in case of a parameter, is it going to lock out all of them?

I know I need to back them up, but I'm by myself on night shift and haven't had the time.
It wasn't a problem 'til the old programmer/operator came back from disability. He's on days and I don't think he likes "change" very much, if ya know what I mean........


Thanks in advance.

I'm trying to remember exactly , but in the parm. page you can change one of the parameters to lock programs within a certain number i.e O1000 and up. Once you do there will be a * next to the number. You can still cut a section out and paste to another program but you can't edit the * no. program. I had a basic template for tool changes that had the program start and end, cut and past and add code. Scroll through the the parms page and see if you can see somthing.
Terry