The installer for GigPerformer5-5.3.3-Setup will not run on my laptop. I installed it on my 1st PC desktop and all OK. But the installer on my second computer, a laptop, just will not run. Has anyone experienced this?
Please delete that setup file and re-download it again. (Maybe the download was incomplete)
If there are any errors, please create a screenshot.
Wow. Thank you. This was very strange. On my desktop the setup worked great. I copied the file onto an external drive and even though it looked fine it must have got corrupted. So thank you. And sorry for the trouble.
I have one question though about this new version. When I installed it on my first computer, my desktop, I did not deactivate. I just installed it and then activated. Will I lose ONE activation as told in an email? Now, on my second computer, I did do that, and am now installing the new version. BUT, my issue is that I have a third computer, another laptop with the previous version installed, and this laptop is in Sydney, another city, ready for a gig there. Will that work, or will I have issues, having lost an activation, OR it will still be activated as I left it last week?
I just checked, you did not lose an activation. All is good.
Yes, only explanation is that it was corrupted in some way (incomplete download, malware, disk issues, or copying error). Glad that the issue is resolved.
Enjoy Gig Performer! 
Wow, super great. Thanks. And so I don’t need to check that 3rd laptop in Sydney? I was going to email a tech there at the Uni where I have left my laptop to check that that third install is still active. But no need to do that?
No need. 
Thanks so much. I really appreciate your support. Thank you. Gig Performer is a super product. And the community is simply amazing.