Wireless Networking Help

I bought a new wireless network card last week - it is here
it wouldn't work so i called customer support. They said it might be something wrong with my router. 5 minutes after i put the phone down it started working. It worked throughout the night. the next day it wouldn't work again. I reused by old USB adapter - it is here
and it worked fine (when i could get my computer to recognise it that is but thats not the problem here)
I don't see what the problem is especially when i got the card to work. If the USB one works it can't be something wrong with my router. I'm all confuzzled

 

my router is fine. Its the network card that won't work and I'm not sure why. I had it working the night i got it but it hasn't worked since. Previously i had a the same thing in a USB device. That works so why doesn't the notebook card?