Screwed up way of working in photoshop.

[Marko pro]

Hi guys.
I am using Photoshop cs-5.
When i installed it, everything worked fine. For while i was using it, i screwed up something and disrupted few functions in Photoshop.
I don't know what the ... i did.
I would be grateful if you help me

First problem is with "Eyedropper tool":

When i am point the cursor on the place which i want and press/holding "Left button" on the mouse, it registered as the 2nd color.

but i want that it register as the 1st color... (here is gray..1st color)..
-At he beginning it registered as 1st color.. now it doesn't want to.
Can i somehow change that again? Please help me

after some time i will post other problems...