a hair dryer repair is really not a repair. All it does is that it changes the shape of the solder bumps. Check on here Hair dryer for logic board reflow? about the hair dryer repairs. Anyhow, that is a different story/answer. Yes, a reball will work but you need to find a new processor to reball it. Using yours “may” work but there are no guarantees.
Here is a very "quick and dirty" explanation of what causes most of the RROD. It is not always a failure of the solder balls which connect the Flip Chip BGA package to the motherboard. It does happen and you can see why [ http://www.bunniestudios.com/blog/?p=223|on here] More commonly however is that the failure is due to the chip design itself.
As you can see the "bumps' are what actually connects the die to the substrate to make the chip complete. If these bumps fail the die does no longer make contact either he substrate and thus no contact with the circuit board. The chip has failed.
Here you can see the space where the bump has failed and no longer makes contact. We are talking microns of space here. So a bit of pressure on the top of the die potentially close the gap. Same with a reflow, it may allow some of material from the bump to reshape and starting to make contact again. The heating of cooling of the chip during use is what will eventually cause it to fail again.