Unless you are configuring a "Port Forward" (possibly for P2P file sharing purposes) then there is no need to use anything other than the "Obtain an IP address automatically" in "Internet Protocol (TCP/IP) Properties"
One major problem with setting a fixed IP address on a network is that if that PC is not switched on first, the router "will" automatically assign that IP address to the first PC that is turned on.
So if that is the case, when you turn on the PC with a fixed IP address, the IP address has already been used by the router and you will then have connection problems.
One way around this "if this is the case" is never to assign IP addresses starting from the lowest IP numbers first.
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If it ain't broke.
Don't fix it.