usb 3.0 not working

usb 3.0 driver not installing

it says compatibilty issue when i troubleshooted it..i am using dell n5110 and driver is wiston 3.0 driver...

i reinstalled win8 and installed win7 but not working..

also i have wifi problem sometimes wifi is not there in wireless networks(lan and wifi adapter changing there) i have to restart the system to enable wifi..pls help me...