First, I'm not even sure this is a computer problem. I have an HP laptop with Verizon fios as carrier; I do not use wireless, only connected. For about the last 6 months or so (spanning winter thru summer), I've noticed that when my HVAC does a periodic "hard" (makes a clunk noise) shutoff, it immedicately knocks out my PC and my modem...shuts down the laptop completely. I have the PC/modem connected to a UPS (uninterrupted power supply) with 625 volts/surge protection/power backup. I have my HVAC serviced 2 times/year, and just had it serviced last week. I have not noticed any other problems with any other appliance/lights/TV's affected by this...only my computer/modem. I know this cannot be good for my laptop, and am at a loss as to how to proceed. I thought the UPS would resolve the problem but that is not the case. Any one else experience this problem? Any thoughts? My printer is also connected to the UPS, but does not seem to be affected when this problem occurs. I live in a 2 level townhouse, with the HVAC on the first level (in the laundry room), and my office (most living space) on the second level. When this happens, it does not trip a circuit breaker. I aplolgize in advance if this is not an appropriate question for this forum.