Some errors and dual boot issues

1. i encountered some fatal virtual monitor error, that seems due of some wrong drivers installed by parallels in the first boot of my xp partition , HOW CAN COMPLETE REINSTALL AGAIN??? as to install a correct drivers?

2. I have triple boot of mac os x , xp and vista, my boot files are stored in xp partition, so i just can't boot up my vista partition by parallels bootcamp as there will be a "missing operating system" msg pops up, how could i boot up VISTA??

thanks in advance!!