Lack of memory for starting up Minecraft. (It stops responding before completing loading bar)

I can open the launcher fine and launch a version fine but towards the end of the loading process in the game window, it stops responding no matter what version I launch.

I've tried:

• Changing the JVM Arguments to something bigger than -Xmx2G (such as -Xmx4G or -Xmx6G) but it just comes up with the same issue.
• Uninstalling and reinstalling the Minecraft launcher.
• Updating my Java version.
• Checking to see if my drivers needed updating.

Not sure what else I could try, any ideas?
It also just doesn't tell me the reason for crashing.