When I connect it with my computer, it make a sound recognising the device but if I try to open Computer to find out the device, it dosn't show the device and ,to make it worse, the window of Computer does not work properly.(Really slow and sometimes stops working so I need to use the task manager to close the window) The power and Actvity lights are on and the fan inside seems working. I also try it on many other computers but still have the same problems. I bought it about 7 months ago and I had the problems since last week.
Please help me out with this.

Computers & Internet - Dane-Elec