We have been in the IT industry since 1990 and since 1999 we have been gathering data from our repair facilities. We would like to share with you the following information :
 

99.3% of all computer repair were software related
00.7% of all computer repair were hardware related

89% of software related repair was due to Viruses and Trojans
21% of software related repair was due to Software conflicts

84% of hardware related repair was due to Power Supply failure
9% of hardware related repair was due to Hard Drive failure
4% of hardware related repair was due to Memory failure
2% of hardware related repair was due to Motherboard failure
The main cause of hardware failure was due to:
68% Hydro source fluctuations
29% Dust accumulating inside the PC/Laptop
2% Hardware malfunction due to tampering
1% Hardware malfunction due to life cycle