After wubi didn't work (error: prefix not found), I decided to perform a native Ubuntu install.
Before that I changed and checked my BIOS already.
First I downloaded an 11.10 iso from ubuntu.com and burnt a CD. Didn't boot.
Then I bought a 11.04 CD from a bookstore. Still didn't boot.
Next, I made a 10.04 USB drive. It booted and installed, but my computer shows grub rescue after the third bootup!
After 5 hours of restoring the windows bootloader, I borrowed the Ubuntu 11.10 Unleashed 2012 book from the local library. It came with the Ubuntu 11.10 DVD Edition CD. STILL didn't boot. Then I booted into nomodset mode and it still didn't boot. The book was new (according to the staff)!
This is what happened all the time: After it shows the purple screen I chose English and chose to try Ubuntu without installing. Then a blank screen with a flashing line appears, sometimes with a "prefix not found" message. It kept flashing for an hour.
What is the problem here? Any help will be appreciated!
ASUS F81SE, 4GB RAM; came with 2 GB, Windows 7 Home Premium; was going to dual-boot