I've had my newly built desktop crash on me for weeks at a time, sometimes coming as far as a normal boot, otherwise having to resort to safe mode. I've pretty much updated every device, driver and chipset there is, but still it screwed me over with crashes. It all started with that horrible, horrible piece of sh*t software from Asus. I've downloaded several versions of said driver, from the newest one to the oldest able to handle 5Ghz connections. There is one crucial thing I forgot about: Windows update.
Eventually I came here to find a solution, and just to help people out who still, like me, are at a loss why in 2019 this bloody thing wasn't ever fixed, here's my solution based on all your input:
0) doublecheck, via device manager, the driver version you have installed. It is highly likely it is a 2017 version if on an updated Win10 machine.
1) download the 2.0.8.8. version from the asus website, select win 10, select view all, and download the last one in the list. check to see its 2.0.8.8. Do not install it yet.
2) Uninstall the driver of the PCE-AC68 through Device manager. You will lose your internet connection, so step 1 is important.
3) restart the computer in safe mode - without networking (shift click the restart button through windows start)
4) install the 2.0.8.8 driver from step 1.
5) important: when succesfull, immediately disable the automatic download of system drivers. press the windows key and when the start menu pops up, start typing 'device installation settings'. A menu item will appear, click on it.
6) click on 'no' in the following prompt. It says some really ambigious stuff about 'manufacturers apps', which just means drivers.
7) restart the computer.
I got the drivers to work several times, but noticed way too late that windows update would overwrite the stable drivers all the time, and as such kept crashing the pc again and again. Do keep in mind that windows update won't download drivers anymore, so keep your computer up to date on your own.