removing a virus from Laptop

How do I connect my Vista Laptop to my XP Desktop to use a virus removal tool controlled from my computer and remove virus when laptops system will not reboot? Laptop system turns on but a blue screen comes up with an error code that will not boot system due to incompatibility of a software program previously downloaded. Cannot get into Windows to remove program or system restore. Lost Adm password but ran all memory and all hardware tests which showed no errors in system. Ran a full diagnostic test and it passes. Try to put in System Vista CD to restore system and same blue screen error. Can't reboot system. Do I need to replace the hard drive?