*Go to A-CP/Templates & Style/*Your Theme/Header Templates/header_welcomeblock_guest
*Replace All content by this
Code removed
*Try To change the url's.
Why is there a table closing tag in the beginning of the code? That's not needed. You just copy-pasted the code out of the welcomeblock template of some theme, which seems to be Dark Orange. And why would you include your forum url on the code, some newbies might get confused, plus there's a path to a specific theme which some users might not have.
And that's not the code, it's a little messy. There's not even the current time variable. It seems you copied the code of the source-code, because the source-code doesn't show variables, it shows the output. So most likely this won't fully work. I suggest you rearrange this. It's a real mess.
faviouz seems to be correct. I can confirm that this code is copied from the Dark Orange theme. As faviouz correctly pointed out, you have just copied the source code, which is why there are no variables in there. Thread closed. Please do not pass off other people's work as your own.