Welcome to the forums!
 
When you say it's hard to push the button, do you mean that you have difficulty actually pushing the button (it won't go down easily) or you have the push the button down unusually far before the mouse is responsive?
 
In the first case, there may be an issue with the internal board slightly being offset which would make it difficult to click. 
In the second case, there may be a spacing issue or the button itself may be defective. 
 
You can try removing the cover http://www.evga.com/support/faq/afmviewfaq.aspx?faqid=59483  to see if you can adjust the placement or if you can see any issues, otherwise I would recommend contacting us directly at support@evga.com so we can assist with an RMA if necessary.