Is This Possible?

(Yes I Know This Is A Duplicate Thread, I'm Going Away For The Week And Wanted To Get It Up, You Can Delete The Other Thread)

So what i was thinking of doing is this

1. Creating A Program That Will Run On Startup (easily done)
2. Said Program Will Lock The Computer if inactive for set ammount of time (changed with a slider)
3. Program Unlocks With Password That Is Set (No Idea How To Do)
4. Make Program Unclosable So You Cant Alt-F4 Out Of It (No Clue)
5. Make It Check If The Browser Is Running A Flash Video So It Doesn't Lock While Watching Youtube Or Check If A Certain File Extension Is Running Then Dont Lock(No Idea)

Just Checking To See If It's Possible Before I Do It.

Basic Screen Design

Home Screen: http://puu.sh/1u6xL
Settings Screen: http://puu.sh/1u6BF

Things I Dont Know How To Do

1. Adding It To The Registry Startup, Would That Make AV's Have A Heart Attack?
2. Changing The Slider Values
3. The Explorer To Choose Only Picture Files (jpg,png,so on) and not .docs and stuff
4. Would I Really Have To Encrypt The Passwords?
5. Where Would I Save Said Passwords? Or Would I Make An Installer?