Since the end of 2018, Act! corporate has cracked down on how many PCs can be installed per Act! user license.  In other words, if you have 5 Act! licenses, you can install it on 10 PCs.  As you replace PCs, you will need to de-activate the license on the PC you are about to replace before installing Act! on the new PC.

If the PC hardware failed before you can do this, you need to call Act! corporate customer service and manually request they de-activate the PC off their list.  Act! corporate tracks by using the UNC name of the PC (ex: \\MONDO-LAPTOP).  This video shows you how to deactivate the license.