I wonder if you have a bad burn on the cd , or the downloaded iso isn't right.
You can check the iso's md5 sum using a windows based md5 checker, look in the download section of someplace like cnet.com for a freebie.

If possible, take the cd to another pc and see if it works on it.

Keep trying the cheatcodes too, press f2 when get the boot prompt. You can't anything hurt by trying. ie: knoppix nousb etc..

Good luck!