Wincc question? Where do I find tag info?

I am pretty new to wincc and just upgraded an older wincc interface to the latest version, the issue that I have is this. I have temperature and pressure readings on the screen while the machine is running, after the upgrade some of the functions work while others don't, what I need to do is to reassign the tags so that it pulls the data from the right place. The Plc is Siemens 300 and step 7 software in statement mode. I just need to know where the data should be changed in wincc as I think I can figure out the rest. Thanks in advance for any help you can give me.
Mark Coates

can you please tell me, about the tag (are they internal or external) you used in wincc..?
check the connection b/w winncc&300 on LHS on wincc screen it should be "connection_1 simatic S7300/400 on"
some times there are unnecessary tag not of use in the "tag screen" deleate them
otherwise chek the properties of each tag again....

If it is exter.nal tag, then check
WinCC Explorer\Tools\Status of driver connnection.
It should say "OK" and not "Disconnected"

You will find tags in groups under each communication channel, depending on the way WinCC talks with S7.