Is there any problem with still using Windows 7?

For various reasons (mainly preference), I use Windows 7 on my main laptop. I use it for work, but also for browsing and, yes, for pornography.

I don't use an antivirus, but I'm careful not to click on any junk and don't install suspicious software. I recently ran Kaspersky's virus removal tool and everything was fine.

I lost my original disc a long time ago and I can't find anything in stores. I've downloaded a iso file but I can't find any available licence keys. I've watched some guides about activation scripts such as HWID, TSForge but I've read that these only last temporarily and may break at any time.