Eugene's observations

You see a message similar to this, what does it mean and what should you do ?

Another computer on this system has the same Ip address as this computer. Contact your system administrator to resolve this issue. More details are available on Window Systems Event Log.

or

There is an IP address conflict with another system on the network.

This type of error can occur for several reasons:

• Two (or more) computers on the LAN are manually assigned the same static IP address
• One computer is assigned a static IP address within the range that the router (DHCP server) dynamically allocates.
• A malfunction in the router allows the same address to be assigned to multiple computers.
• An Internet Service Provider (ISP) accidentally assigns two customers the same IP address (either statically or dynamically).
• A laptop or other mobile appliance is put into a sleep state and then awakened. During the period of sleep another computer was allocated the same address.
• A badly configured computer may experience an IP address conflict with itself if it is configured with multiple network adapters.
• System administrators may also create IP conflicts by accidentally connecting two ports of a network switch or router to each other.

The solution is to shut down all computers and power off all network connected devices. If feasible, power off the router (DHCP server) also. After two minutes switch them on, router first then the other device(s) leaving a minute between powering each one on. If the problem persists, all in 1ComputerCare to the rescue.