"The product code you've entered is invalid..

[VeZ]

I have tried my cdkey atleast 10 times, each time carefully looking at it, ive even used a magnifying glass and I am positive I have entered the right code. Is there anyway to fix this or do I have to go to the store and attempt to trade it for another one

 

[VeZ]

Ah i just restarted steam and cancelled all my preloading on EP1 and it worked the next time