Network Adapter is Experiencing Problems/Default Gateway

I'm using an ASUS X550LNV running Windows 8.1, and it was running fine up until about a week ago, when the network adapter started messing up. I'll be running fine for a while, anywhere from a minute to hours, and then I'll disconnect. It will tell me there's a limited connection, and then I use the troubleshooting to reset the wi-fi adapter. Sometimes that fixes it and it tells me it fixed the problem of "the default gateway was not available." Other times the adapter disables and troubleshooting can't fix it, telling me "Realtek 8821AE Wireless LAN 802.11ac PCI-E NIC is experiencing hardware or driver related problems". If I try to scan my device manager for hardware changes, the adapter disappears. If I try to enable it from the list of network adapters, it says it's enabling and nothing happens. The only way I've been able to fix it when that happens is restarting the computer - and sometimes it stays disabled when the computer restarts, although then it lets me enable the adapter to fix it.

I've downloaded drivers from the ASUS website. I've looked other places to see if there are more recent drivers. I've refreshed Windows to get a reinstall. I've checked my registry for upper and lower limits. I'm at the end of my rope in fixing this issue, and I'm beginning to think it's hardware-related and my computer is kicking the bucket. Any ideas anyone could share would be really helpful. Thanks so much!

Borrow or Buy a USB WiFi dongle, dual range would be best to go with your AC router. I suspect this would show you the fault lies in the onboard adapter or driver, I use a Netgear AC adapter, even though the onboard works fine for the 2.4 range, I prefer the 5 gHz range of the dongle.

I would be thinking Channel congestion. Open up a CMD window as admin (Windows key "X", then choose Command Prompt (Admin)). Type or copy the following: netsh wlan show all
Then right click on the top bar of the window, choose Edit in the menu, then Select All, then Copy. That output you paste into a post on here. It will give us all of the info we need to diagnose why this is happening.

As for Limited Connections, it can be due to a messed up IP Table or DNS table on your computer, Could also be the Gateway is having IP conflicts, if you are using static IP's on computers, or MAC to IP on the Gateway. Can also happen if you hide the SSID. The other can be third party Internet Security Software.