computer

[blackfish]

When I switched on my computer there was a message (net work error)
that another computer was being used with the same address as mine

[kujawski]

ok XP or previous

Click Start > Control Panel > Network Connections >
Right click 'Local Area Connection' and select properties

Highlight 'Internet Protocol(TCP/IP) and select properties.

if 'Use the following IP Address' is checked then its likley that both computers have the same IP address (ie: 192.168.123.100), hence your message,
simply change the last set of 3 numbers to something else, (making sure that no one else has used this address)

you can first check if it isnt already on the network, by
clicking start > run > type cmd, click ok and type ping (your new ip address that you want to use)

[kujawski]

may also be an idea to

Click Start > Control Panel > System
select 'computer name' tab and make sure that its name is also unique on the network, if not then change it.

[ACtheTROLL]

when you say "your computer" and "network"

is this at work?

if it is your tech guy needs to be the one who sorts this out
especially if you are using static addresses - you could take the whole network down by following kuj's advice.

[kujawski]

so how will it 'take the whole network down' then???????

[kujawski]

most that will probably happen if its wrong is you wont be able to connect to your network using said computer,

[kujawski]

actually your quite right AC,

its best if its a works pc to have the tech team deal with it, as you dont quite know what may happen

[blackfish]

Thanks for advice. As I am a complete novice I think I will take it to my local shop ( nice helpful man in there)