Re: Yuri's Revenge Serial number issue.
Ah, that issue...
The problem here is that I think the full-hard disk install of Yuri's Revenge doesn't actually set a unique serial in the system registry.
To solve this issue, you need to start regedit (just type it in the start menu), go through the tree to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Westwood\Yuri's Revenge (for RA2, the key name is "Red Alert 2"), and find and modify the "Serial" value in there.
[edit]
If the "Serial" field does not exist, right click, select "New" -> "String value", rename it to "Serial", and then edit it and type anything you want in there, and make sure it's different on the two PCs.
Note that the "Wow6432Node" node between "SOFTWARE" and "Westwood" only exists on 64-bit systems. On 32-bit systems it'll just be "SOFTWARE\Westwood".
I don't think the game actually requires a valid serial there; only the original CD installer checks that, not the game. But for network play, it does need a unique one there. So basically modify it to anything random you want, and as long as it's not the same on both PCs it should solve the issue.
