Arch Linux shows a blinking cursor instead of a booting installer. I ran
sudo dd if=archlinux-2010.05-core-i686.iso of=/dev/sdb1
and checked the MD5 sums.
I tried to boot it on two different PCs and got the same result: instead of booting GRUB — or anything useful, for that matter — it just showed a blinking cursor at the top left corner of the screen.
The machines became unresponsive to any kind of input, the flash drive LED didn't seem to blink or shiver at all and there seemed to be no other activity whatsoever.
I tried using another flash drive, but the machine completely ignored it, booting Windows "normally."