Why do I keep getting a bubble pop-up that won't tell me what the problem is?

First off, I have Vista. Which sucks. Recently I keep getting this little pop-up that says "windows has blocked some programs from running at start up. click here to see what programs"



Then I click the bubble to see what is being blocked and it shows nothing.



So my question is why is it doing this? and what would it be blocking?Why do I keep getting a bubble pop-up that won't tell me what the problem is?
Actually not entirely a vista thing. XP does it too. This happens usually when you changed what start up programs start up when windows does(through msconfig or some other program) And the program itself is still set to auto-run. What happens is the program tries to run on startup but your system is set to not start that up so it blocks it. Then you get your little error message saying it blocked this blah blah blah... Usually if you just click the don't notify me button it goes away and all's good. Why do I keep getting a bubble pop-up that won't tell me what the problem is?
You probably have a virus, which might explain what it's blocking and why you can't see what it's blocking. You should just clean out your computer. Transfer files you need onto another place and reset the computer. Why do I keep getting a bubble pop-up that won't tell me what the problem is?
You have to right-click it, which gives you a few options. One of them has an arrow next to it which gives you a list of administrator-level programs. You can click them individually to allow them to run.
You have used a program similar to MSconfig32.exe that will give this message every time until you turn all programs on or change the setting for Startup. You have stopped a program from loading at startup.