No startup without usb-stick

Hello computer men and women

i just installed the 10.04 netbook version on Compaq mini 110 via usb-stick. Chose to install it on the harddrive, one partition for the complete harddrive. It worked fine.
First startup with plugged stick was ok, and I changed the boot device order to HD. Second startup didn't work without stick. Restarted with stick, it worked.
Now, even after trying all the combinations of boot device order and stick/no stick, all my startup attempts fail. There's just a cursor blinking on the upper left of the screen. Funny fact: when it worked, it did with an empty stick.

Thank you for your help.
Karl