lol i am not trying to cure the problem… we are trying to diagnose the problem,

IF- the space heater causes the computer to work, Then - then its something like a BGA issue or

loose connection that expansion from heat fixes, Then you get a idea of the kind of issue you are dealing with,

in one of the 3 powermacs i worked on, i found the issue was just the video card needed to be pulled and reseated...

with the space heater:

( were talking like 160 F tops ) by the way,,,

IF - the issue happens to be BGA, Then- you will need more then just a heat gun,

to fix the issue-