Preventing from virtual damge
1) good antivirus
2) Legal programs
3) Legal OS
4) Safe browesing
5) Use spec. programs or app's for system cleaning or program uninstaling
6) have a backup
Prevent from Real damage
1) Try to make it waterproof and bulletproof
D just kidding i heard something about sprays or something wich prevents from water
2) Good cooling! safe Temp and good PC work
3) Cleaning dusts every week
4) All cables and fans are in right positions to be sure that any cables or wires are cut
5) Safe place! from small kids and animals
6)Try not to do overclocking pecouse it is harming you system
I could tell you more but i don't have much time