Minecraft freezes when opening another program

If I have Minecraft open and I launch the browser or another program, Minecraft doesn't react any more ("Minecraft 1.8.1 not responding"). I am getting this error:

[0x7FF936E3C1F0] ANOMALY: meaningless REX prefix used
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ff94b193924, pid=4708, tid=1216
#
# JRE version: Java(TM) SE Runtime Environment (8.0_25-b18) (build 1.8.0_25-b18)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.25-b02 mixed mode windows-amd64 compressed      oops)
# Problematic frame:
# C  [OPENGL32.dll+0xe3924]

I found some solutions online and tried them, but they didn't work:

• Reinstall Java
• Reinstall Minecraft
• Install java JDK or JRE

It does work if I take out a random USB stick, but this is just temporary. I want a permanent fix. Anyone know what i have to do?

I am running vanilla Minecraft 1.8.1.

I have a Sapphire Radeon HD 7770 GHZ Edition GDDR5. My driver version is 11.2, the latest according to the website and the auto detect and their app.