Okay, I tried a different USB-port and now it does boot. It even goes to the installer et all. I partitioned my drive like the install-guide from tony says. All goes great until the actual install. It started to fill the blue bar for a while, but now it just hangs at "Remaining time: 19 minutes" and the blue bar doesn't move anymore. The light of my USB-drive does keep flashing like normal though. But the installer just hangs, no mouse movement either.
What to do now?
Edit: weird. I hit the power button once and now it's over 50% and mouse working again. As if it was sleeping and I woke it up by hitting the power button once.