Most likely source of a fire is that plug-in protector.  Read its numbers.  How many joules does it claim to absorb?  Hundreds?  A destructive surge can be hundreds of thousands of joules.  Some (even fire houses) have seen the threat.

Your computer will even convert hundreds joules surges into rock solid and stable low voltage DC to power its semiconductors.  That same energy could even destroy the protector.  If a thermal fuse does not blow fast enough, then catastrophic failure (worst case a fire) can result.

APC recently admitted to maybe millions of their protector must be removed immediately.  View a CPC.gov site for further information.

A computer that overheats only crashes - mis-executes software.  No hardware damage.  Let hardware cool and software works just fine again.  Insufficiently cooled computer does not create fire - does not destroy hardware.  Furthermore, heat is a powerful diagnostic tool to locate defective hardware.  Any computer that does not operate in a 100 degree F room may have defective semiconductors that will get worse with age.