Bad High School marks, university off limit?

Seek the advice of the proposed university admissions persons . . . in the meantime, I'd suggest going to community college, as that's gonna get you further along than the high school grades. It's one thing to say that you HAD to attend high school (and perhaps you don't have the best grades); yet, it's another to show that you CHOSE to attend college (and got better grades). Start working towards a two-year certification in some discipline that you may transfer to a four-year program. To get to your PhD, you have to take baby steps toward your under-graduate work . . . and hopefully all the courses you take will help leverage your PhD.