Do you have non-legit windows 7?That's ok have this free windows 10 upgrade anyways,says microsoft.

You will be able to upgrade your copy, but it will still stay pirated (so no free licenses)
http://venturebeat.com/2015/03/19/microsoft-says-free-windows-10-upgrades-for-pirates-will-be-non-genuine-and-unsupported-stays-mum-on-security/

I have a licence that I got through my university, I wonder if I'll be able to get a free upgrade that will not be bound to my uni.

hmmm might have to find a copy so can dual boot windows 10 along side my trusty windows 7

I have this icon showing up on the taskbar on the lower right saying i can reserve a free copy (i am not in china), but it doesn't seem to be clickable to get it away.

Of course they will give it for free, they're not doing you a favor.

The OS has a built-in keylogger. 'nuff said.

Assuming I have an OEM version of the current OS, will there be a problem if I have to reinstall Win10 after the migration period is over?