I bought an Aspire E5-575 and had the same problem. It's the first time I bought ACER so, I had no idea in what I was getting into.
I tried to work the problem out with the ACER online chat help. Don't waste your time.
Then I went to the source of all contemporary knowledge: the Internet, which to begin with showed me this has been a common problem for ACER for a very long time. I was already regretting the purchase with all my guts and after reading multiple treads about this, I did what finally worked for me. Here it is:
- Go to "Device Manager" and click in the little arrow to the left of "Network Adapters" to open all the devices.
- Right Click on "Qualcomm Atheros" and click in "Properties"
- Click on the "Resources" tab and click on "Wireless Mode"
- Change "Value" to "01-11b" (it was set in "12-11a/b/g/n/ab")
- Click "ok" and make sure you are connected to your wifi network.
That's it. That worked for me although, to be honest, I don't know what I did so, if somebody think this was a bad idea for any reason, let me know.
Otherwise, enjoy your wifi.