Jump not working

[NOOBHERE™]

Alright i just bought a new keyboard for my computer and i have issue with it already.
When I play css I have problem when I press the (shift) key to duck and the (W) key to move forward and holding them , when I press the (Space) key to jump it wont work. It only works when I only press (W) key and than jump Or (shift) key and not pressing on the (W) key it will jump, and than ill be able to press the (W) key. Tho if I press like (A,S,D) keys they will work. or even if i change the (SHift) key to (control) than ill be able to press all three.

I have no clue how to really explain this so sorry for my english

http://www.logitech.com/en-ca/product/illuminated-keyboard-k740