PC won't open certain programs - Please help

[Utaheka]

Hello SevenForums.
I have an issue with my Windows / my PC, that I hope you can help me with.
Last night I used my PC just fine and so on.
But when I turned it on today and logged in I couldn't open my most used programs (StarCraft II, Windows Live & Firefox 5 - Dunno if there's more).
I find it extremely ordinary, and it has never happened before..

What happens is, that I click the shortcut and nothing happens. I tried editing my exefile default to something else, but this doesn't work either.
I thought to myself: Oh well, I'll just uninstall - but NO! I can't even uninstall the programs.

I certainly hope you can help me with this issue!

Best Regards,
Utaheka

 

[Utaheka]

And by the way, I don't have any anti-virus because I find it unnecessary. - And also I've tried to system restore to a point of time.
None worked.

 

[Utaheka]

Nothing happens at all... No errors etc >.>