Okay this may sound stupid but in RoTF Leo tried to touch the glass that contained Frenzys head and Simmons said "Don't touch that its still radio active!" Now we all know that Frenzy's spark is in his head so could he still be alive? Discuss!
If he were, I'd think his head would've grown little legs like it did in the first film by now and ran away.
Ha. Well, I wonder if he'd be too traumatized to come out at night given what Simmons might be walking around in during the wee hours. I wouldn't want to come back from the dead to see Simmons in his skivvies or less while flipping through old files down in his hole.
in the RotF book Frenzy is still active, his head chained to a table in Simmons apt. The reason he moved the head under his mothers deli is because while experimenting with the head he hooked it up to the fusebox in his apt building and it started going apeshit.
For all we know, he could just be off-line. And, technically, every part of his body is alive, so having his head cut into two pieces probably DIDN'T kill him anyway.....