USB ports not working
I have late 2011 macbook pro 13.3 and usb ports are not working. One port is like dead and isn't working at all. Other is working perfectly when I put my mouse receiver, but don't recognize any flash drives or other devices, but I can see what is plugged in this port in system information/usb. For example, if I put my phone into working usb port I can see in system information/usb that Samsung Android is connected, but that's it is all I can do. Disk utility don't recognize anything...
I have tried to format the hard drive and downgrade my os x from CD, but that haven't changed anything, so probably it isn't software problem.
It would be so great if you could tell me what can be wrong with my mac, because now I just don't know what to do.