For no apparent reason my USB Wireless network antenna has suddenly stopped working. I have power to the unit but I am getting no signal whatsoever.

This also happend to SuperG PCI Wireless network card that I bought for it a few months back it was fine for about 4 months and then suddenly stopped working.

Obviously I need to get my USB wireless network antenna working again. Grrrrrrrr I am so annoyed. Has anyone got any ideas?