network issue - media disconnects

I have posted in software, cos I think it may be a software issue - but please advise and I can post elsewhere.
Running windows 8.1 and using a wireless connection to network. Usually all is great. I have a static IP set up (so my tablet can access my ebook library on the calibre server running on the PC).
every few days (between about 4 and 7) when I access the computer the network has the yellow !. I can see wireless networks, but can't connect.
an ipconfig reveals the media is disconnected.
the "change adapter settings" ignores my efforts to click on it.
A reboot always fixes it.
I have tried flushing the DNS and the obvious troubleshooter - all to no avail.
I have stopped the adapter going to sleep to save power - problem persists.
I would really prefer not to have a dynamic IP address.
I have very little network knowledge and so don't know what info is likely to help. In summary, things are usually working OK so the basic settings are OK, every so often they break and a reboot fixes it (hence my thinking it is a software issue).
Any help appreciated.

 

See if this coincides with the IP address lease timing.
Be sure your DHCP server knows all about your static IP and does not use it.

 

Thanks for response.
I am using the 192.168.1.* ip addresses off my router and the IP address I fixed is 192.168.1.16.
I can't find the lease time in the ipconfig /all, but I have changed the way I have fixed the ip address so it is now the router which does it (based on MAC address) and the PC just gets the IP address assigned automatically (I used to fix it through the network adapter settings).

I'll let you know if it is still working in a week!

 

so far the network has been working for over a week - the longest ever on this PC. I guess it is getting the router to assign the static IP address rather than having windows do it. Thanks to DOA for the pointer to the lease times.