|You can but the second computer won't be legal unless it too has the coa sticker on it.|
The biggest problem is when computer 1 is a Dell ,hp Acer etc,and computer 2 is another brand. You will usually need to do a search for drivers. You will also need to use the dell keys..... to install and then update the keys for the other brand. Microsoft has a free key updater to do this.
It has been an ongoing debate the legality of this but I feel Microsoft wouldn't have a key updater if they expected people to go out and buy a cd for every brand of computer as the coa is the license. (Just my opinion and yes I have read the EULA .
If you are asking "Can I use the same keys on two computers."...yes.
"Can I activate both" Yes
"Can I update both" Yes
"At some time will one or both receive a message that the license has already been used and one or both copies are illegal?" Yes
Hope this of some help.