READ THIS: I got myself a DVD-drive and burned the ISO image on a DVD. The same problem still occurs without an USB device.
I'm trying to install Windows 7 Professional SP1 using a USB stick.
The installation slows down when I see the glowing Windows logo and the "Starting Windows" text. The logo animation is running and HDD led is on so I'm pretty sure it's about ridiculously slow I/O speed.
My motherboard is Asus P8Z68-V/GEN3.
What I've tried:
Different USB sticks
Different USB ports
Booting Ubuntu from the USB sticks (It's fast!)
Recreating the USB stick's contents
Finding floppy related settings from BIOS and disabling them. This was mentioned on few sites I found using Google. Sadly there was no settings related to Floppies. I can choose whether to boot from the USB device as a "Floppy", "Force FDD", "Hard disk" and "CD-ROM". I've tried all of those and only "Hard disk" seems to work.