macbook cannot delete any partitions

i recently just installed windows 7 and in the process i think i accidentally deleted one of the partitions which is disk0. my macbook is in mbr so i cannot do a clean reinstall with the recovery disk in the lion osx. i have searched everywhere and it seems like my problem stems from a chain reaction of some sort. my bootcamp assistant says to partition to a single drive. i can't even delete my bootcamp partition in disk utility because it's greyed out. when i try to partition a drive through the recovery hd there is an error that says 'could not unmount disk'. i have exasperated all the possible options and i have no idea what to do now.