Sometimes the router IP DNS address causes problems like this. A solution to some issues involves changing the router IP DNS address to an OpenDNS address. The two to try are 208.67.222.222 and 208.67.220.220. Write down the current addresses if you need to return. If you don't know how to get to the router settings, search the web for the procedure. The initial step is typing the router address into the browser site line. Many addresses are 192,168.x.y, where x=2 and y=1 or something similar.
Running Windows 8.1 (64) on Inspiron 15 (5537, mid-2013) laptop.  I'll start by saying that, to solve this problem, I've read the sticky on this forum, I've tried the windows-driven troubleshooting, the Dell web-based diagnostics, multiple tutorials, and searched forum archives. A month ago, the wireless began disappearing.  It's not that I'm losing the signal, and it's not that the wireless is disabled (not being firewalled or disabled by power saving options).  The card disappears: the unconnected ethernet icon appears in the tray, and there is no wireless card to be found anywhere in Windows.  Sometimes it's not there on reboot, sometimes it disappears after a random amount of time of use.  For the latter, the signal disappears, no networks are detected, then the wireless disappears, in that order. Initially, the card would reappear on reboot.  When this "fix" stopped working, re-installing the driver (and rebooting) would "fix" the issue.  Now, neither work.  My wireless card is not recognized (i.e. "disappeared", although physically it's still there of course). Thoughts? Replace the card?  Where can I get one? Thank you for your help!
Inspiron 15 wireless disappears