yes, as Paul was saying, we need to know if you are trying to connect to the internal or external IP. if you are connecting to an IP which looks like 192.168.0.8 or 10.0.0.24 then it is internal. if it's not then you will probably have had a VPN connection set up. check to make sure the VPN connection is connected if that is the case.
where was the powercut? was it where the server was held? if so do you definitely know it's turned back on and has booted up fine? if you can get someone to tell you the name of the server, which could be something like "office-server-02" you can try and log in from there.