First and foremost, sorry to hear about your loss and situation. I will be praying for you.
(sorry for the long post)
As a long time computer tech I hear about these types of things all the time. Having a father with almost 30 years at a power plant plus fire department allows me to see and hear the stories of what is possible.
There can be several causes:
First the age of the house, if it was built from 1990 or older, then it likely has 12 or 14 gauge wire (or smaller in rare cases if the builder went cheap) instead of the suggested 10 gauge, which over the span of the entire house means it can be spread thin. Get a high powered draw on it like microwave, several computers, cheap surge protector, stereo equipment, big (tube style) TVs and so on, it can cause all sorts of problems.
My house was built around 1980 so this is why I have mostly switched to lower draw LCD screens (TVs and computer monitors), more efficient power supplies in the computers and $40-60 surge protectors and battery backup. With 3 computers, 3 monitors, decent 5.1 speaker system, printer and the usual small items, I have measured the total power draw is just under 400W which is well within the old wiring capability. I have seen spikes just over 500W when I do some gaming where the video card, power supply and speakers are working harder but that is still within the maximum 800W max draw for the house wiring (14ga wires) in this room to the junction box.
Second, many times they are actually just a power strip, not a full surge protector. In those cases putting too much power can result anything from tripping the internal breaker on half decent units to causing the fire as seen from the original poster. Cheap units that also label themselves as a "surge protector" may be nothing more than just have an internal breaker that is supposed to trip if too much power (over 15A) tries to get in or is being drawn through it. If that breaker fails to do its job then we see the situation as seen in the original post. Stick with quality names, and ALWAYS look for a "Joule rating". The higher the joules the better the protection, but at minimum try to stay over 2000 Jouels per computer. 3 computers = 6000 joules.
Some quality names: APC, Belkin, Tripp-lite, CyberPower, Fellowes
It may help to spend $70-80 on a small battery backup unit, not for the battery protection but they also tend to have voltage monitoring, so if the computer tries to draw too much it will limit the power itself to prevent it from overloading. Also if the voltage drops or spikes, it will cut external power and use battery power until it returns to normal, many times just a few seconds. I usually hear mine beeping at minimum once a day from spikes or drops. Here is the UPC unit I have on my main system and modem/router:
APC BE650G (650VA, 390W). This is only suggested for one computer due to the 390W limit. If you have a high powered gaming computer or want multiple computers on one APC unit, then it would help to get at least a 600W or better unit.
Third, if you are making some home improvements or building an addition for a home office, speak with the electrician and ask him to only use 10 gauge wire in this room and all the way to the junction box on its own 30A breaker. Also having one or more GFCI outlets on the first outlet in the series for that room can help reduce the chance for problems as well. This means you would have 30A protection at the breaker, 15 or 20A at the GFCI (usually 15A for that outlet or 20A for other draw down the line from it), and usually 15A from the surge protector.
In the case of the original poster, I might suggest 10 ga. wire to each room from the breakers, then 12 ga for the outlets, lights, and so on, except the computer room, insist on sticking with 10ga all around that room top to bottom. Some electricians may say that 12 or 14 ga is sufficient, but with my father working for almost 30 years at a power plant AND volunteer fire department, he has seen what electrician recommendations can do (same result as original poster). With more and more electric reliant devices out there, loading up a single outlet with cell phone charger, printer, wireless home phone, electric razor, may seem no big deal but 1A here and 4A there can start adding up quickly and pass the 15A rating.
Wow typed up a lot more than I expected.... as long as it helps a few people I am happy. I am looking for some exact distance and numbers for the various gauge wires but can't find my little black book... may edit and report back later.