Minecraft freezing desktop on launch

When started from the launcher, Minecraft causes extreme lag and freezing in all desktop applications, including itself, lasting for between 2 and 5 minutes. It also seems to cause lag in the desktop itself, sometimes preventing the mouse pointer from moving. It usually causes any open programs to become unresponsive.

I have considered that perhaps this is a computer issue, but I've only had this problem recently and it seems to get worse each time I start the game. Just tonight I tried to start it and it took about 5 minutes for a window to even appear, and when it did everything else froze and I was forced to restart my computer.