Wifi connection locking up - Mint 18.3 laptop
I installed Linux Mint 18.3 onto an old laptop PC which had some serious issues with the original Win OS, I forget which version, the machine was gifted to me to play with. The installation went smoothly and, after increasing the ram to 4GB ran acceptably if not blindingly quickly. In use it wakes up and runs as expected, logging onto any of our Wifi routers and happily running Firefox but, after some time it loses the Wifi link. Hovering over the Wifi icon in the task bar shows the Wifi signal strength high, sometimes higher than it is when it is working, sometimes up at 100%. When working normally the signal strength is typically 85%. When it locks out the machine's other functions seem to be OK and if the ethernet cable is connected to the router, the internet browsing is resumed. The Wifi connection can only be restored by rebooting the whole machine, nudging the network connections by changing which router to connect wirelessly doesn't force reconnection. Refreshing the available routers list doesn't work. The problem occurs on 2.4GHz and 5Ghz Wifi connections.
Is there an easy way to determine if the problem is in the hardware or in the driver software? I didn't use the machine before the OS change so have no idea if the machine lost the Wifi before.
Thanks,
Rans6....................