Vista - installed 3 vistas on 1 comp

hi i have a problem i got a virus so i put in the disk that came with this computer it turns out its a windows vista and not a system restore disk even tho it say system restore now i have 3 vistas installed on this computer and it pretty much ate all my ram is there a way to delete the other two vistas i need help asap this is my older brothers computer

How on earth did you accidentally manage to get 3 Vistas on there??? I'm pretty much sure the ram is ok, but your hard disk space must be tickets about now.

What you should have done to begin with was to perform a repair install.

You only real solution would be to go into the correct Vista installation and then backup to CD or DVD all pertinent data. Boot from the Vista DVD, do yet another Vista install, but be sure to FORMAT the target drive this time.