My dad is good with computers,but I'm better than him now.My mother is something else entirely.
Her laptop has an ATI gpu,a particularly troublesome one that is.The drivers that came with it had a huge problem:a small hotkey program went haywire sometimes and used all the processing power the poor little Intel had to give.
When I asked my mother if this is the first time it happens,she said no,but since she had no idea what was happening,she just ignored it hoping it would fix itself.
Or my sister.Installs some obvious MSN messenger mal/spyware asking her to pay,not letting the computer do anything until she entered a credit card number.She asks my dad for help,who promptly reinstalls windows.First thing my sister does?Redownload MSN and the same malware bullshit.When I saw my dad in the evening and asked why he looked annoyed,he told me.I laughed and "accidently" unplugged the wifi connector on her computer.
Now,as a rule of thumb,I don't trust anyone who puts stickers on his/her LCD screen or has over 1 toolbar on IE while using it,and no other program.