The info you supply is a tad confusing.
Are you booting up from an internal C: harddrive?
Is the harddrive partitioned?
How many separate internal Harddrives do you have?
What exactly do you mean by "I have an external hard drive (the internal ones are properly messed up and unrepairable)"
Why do you think that buying a new external drive will help?
If the burn process is not actually burning anything to a dvd, then it may be that the DVD RW drive is faulty (probably the laser burn head is broken/worn out)
Also which programs have you used to (try to) burn your dvd discs?