DvanR

A decent Solar inverter will not protect you from line voltage ripple and minor surges when you are running from the grid as they run in a pass-through mode. On battery power or solar the inverter output power should be very clean though. Also when the inverter is running from the grid with some load applied load I have found that the switchover response time is not fast enough when load-shedding hits that some of my servers tend to reset due to the voltage drop (my inverter has allready been configured for UPS mode). I therefore run an online ups between the solar inverter and the servers as this type of UPS always converts the incoming AC to DC and then back to AC which ensures a much cleaner supply to the servers and also prevents resets happening during power failure/changeover

If your PC has the usual switchmode PSU providing it power, then it is most unlikely that the Inverter would have been responsible for the failure, the only thing that might cause trouble, that I can think of, is if the inverter does not provide a stable Voltage and dips the AC down to 180V or less, then some PSU's could conceivably do somthing dumb, but its not very likely, I'd think. The only inverters that are likely to put out actual sine wave AC are the transformer designs like Victron, the gaggle of Chinese high frequency inverters approximate a 50 or 60Hz sine wave...

many dodgy china/malaysia/india PSU's floating around that do a poor job filtering incoming power.

Also just as many dodgy UPS's floating around that are not really suitable for PC's

A pure sinewave UPS with a decent PSU (corsair platinum is what I use) and you should be ok

That said, generally PC psu's should be ok behind UPS and usually also ok behind good solar inverters that are correctly installed.

A good surge protector also goes a long way protecting sensitive electronics, they smooth out all those nasty micro/milli second voltage spikes that can mess up electronics.
 
But then maybe it was just time for that PSU to retire

Where are the IT guys. AFAIK all mother boards are powered by DC coming from power supplies and should be clean via all the filtering. This seems not related to the quality of the supply power. 
I stand to be corrected. 

"Clean electricity” is considered good with a THD of less than 6% and often stated or promoted at 5% or less. For units that measure greater than 6% THD the electrical wave can cause sensitive electrical circuits such as computers or other minor electronics, to loose life. Check what is your inverter THD spesification for instance good quality online double conversion ups has a THD of <3% that is normally used in hospitals critical care enviroment.