Can 2 comps have the same IP address?

Today I've got this msg from windows for the first time -- it states that somebody else using another computer on the same network has the same IP address, plz contact yer provider.. Dad was using his computer in another room with the same network, could it be him? But I've never had messages like this before! Is it possible that 2 computers could share the same IP? Thanx a lot!

This occurs when two or more computers on the same LAN network end up with the same IP address. When this occurs, both computers end up not being able to connect to network.There are a few ways in which this problem can be fixed.If it is Static IP request your ISP for a change of IP.If it is a Dynamic IP you can try resetting your modem by switching ON and OFF the modem or open the command prompt and type "ipconfig /release," which dumps the automatic address it had, and then "ipconfig /renew," which gets a new address.To check for the change in IP you can visit Ip-details.com which gives your public Ip when you visit the site.