Yup, with software they catch you out both ways.
First - You have to accept the agreement to go ahead and install/use the software and unlike most agreements written on paper, you don’t even have to sign your name to be locked in to the agreement.
Second - If you don’t accept the agreement, you can’t bring the software back for a refund, at least for most software products. I remember about 6 years ago when I worked for an IT support company, I realised that “Microsoft Windows 2003 for Small Business Server” and “Microsoft Windows 2003 Small Business Server Standard” are two completely different OS’s after a costly mistake!
At the time, I bought the wrong OS not realising it and to my surprise, I could not find Microsoft Exchange, so I called up Microsoft asking how to get it and they said that Exchange is not included with this OS. I said that both the Standard and Premium version comes with exchange and these are the only two SBS versions listed on their website, but they said that the version I have is actually another version (not on their website) and is just Windows Server 2003 with several limitations imposed, unlike the Standard/Premium SBS versions that come bundled with Exchange, SQL, Outlook, etc. Sure enough, I could not get a refund as once the seal on the box is broken, it cannot be returned, even if you don’t even touch the content inside, never mind accepting the agreement at installation.
So with software, always try before you buy where possible! If you buy a printer, phone, kettle, etc. and are not happy, you can generally bring it back for a refund or store credit. If you’re not happy with a software package you purchased, then it is tough luck.