Jimmy, try it on a different computer and it is defective if you get the same problem. Is it brand new?

Yes i went back to the shop and it said the tl-wn823N worked fine on their computer. So... idk, please help :o
Extra info: I can't install any drivers if the computer doesn't detect the wifi device.
extra extra info: i tried plugging it in a usb-hub i have and it does detect some sort of unknown device, but the installation software doesn't say there is one. So i guess it hasn't got anything to do with power suply. Although the led inside the stick doesn't blink.

edit:
Extra extra extra info: i've got windows 7 Home Premium service pack 1 installed on my computer. Could this be of any problem? (i'm going to check if theres some updates)

Any other computers at home for you to test? Probably there is a compatibility issue between your PC and WN823N.