I lwould like to lock the programs on my son's computer so I can prevent him accessing them except for when I want him to? Like IE, games, and others.

Unfortunately there isn't a way to password protect without buying a program that will allow you to password individual programs, here is a link for a program that will do that
Program Protector - Password protect Windows programs and applications
There may be other options, the option above is $29 US

$29 is cheap, don't skip this.

Alternately, you might want to reconsider the whole "my son's computer" thing. TVs and computers in kids rooms are great conveniences, but utlimately detrimental since it provide unrestricted/unsupervised access to both.

One or two computers with BIG screens in the family common area goes a long way to eliminate/reduce improper web use. Same for TVs. Bedrooms are for resting and studying and PRIVACY, don't add computer to the whole privacy thing, it's a loser.

A lot of people will disagree and that's fine. You clearly have a concern, so that's my suggestion. Take the computer out of the room (awwww, Dad!) but at the same time add some great new thing to it like a 22" flat panel. (Yeah! Dad!)

Program Lock Pro - Lock any program on your computer - Free software download.

Just to let you know how I found this program

free program to lock the programs on computer - Google Search

Hope this helps -- Please rate my answer

Have any of you download and use the program suggested??

I personally use exe password, here is the link and it is 19.95
Exe Password Protector, Password-Protect Exe Files, Lock .exe Files
You basically find the file that starts the program
(ex.. c:\program files\internet explorer\iexplore.exe)
Then you right click on iexplore.exe and click "Password Protection" and it gives you a box to type in a password and a confirm box and then when you click Apply, it is password locked
Now if the internet explorer icon is clicked, it will prompt for the password and will not open unless correct