So recently I had an issue where my Minecraft was crashing every time I launched the game, this was made worse by the fact it was stuck in full screen. I had the full screen issue fixed but Minecraft is still crashing consistently. It occasionally works and I think it has something to do with lag, but I and been able to run it on my other computer where lag was more of an issue flawlessly. It will run occasionally, and for some reason it has also gotten worse than before, not to mention this is a relatively new issue for me. When I first got the computer it was just fine, and I have only two other games including Conan Exiles and Ark Survival Evolved, I do run mods with Ark however.
Say something silly, Laugh 'til it hurts, Take a risk, Sing out loud, Rock the boat, Shake things up, Flirt with disaster, Buy something frivolous, Color outside the lines, Cause a scene, Order dessert, Make waves, Get carried away, Have a great day!
As Conor above has said - sometimes there are incompatibility problems with other software - but you may not have any of those program installed
To me it sounds like the actual game & not the launcher at fault.
You say it crashes on pressing the green button (when main game is loading - maybe when Mojang screen is showing, which could be a file problem) but in OP you also say "it will run occasionally", so a crash log would help us come up with other ideas to what may be causing the problem.
I mentioned before where to find the log file, but you can get the launcher to show it up as well (I prefer the folder method usually - it's a standard TXT file that can be attached or copy/pasted into spoiler tags)
To get the log to show up while starting game, Go to [Settings] & switch on the 'Open output log when game starts'
When you start the game you will get a new window pop up that show the current log file & when game crashes the last lines would usually give an idea what caused it (although having the full log file is more helpful)