What sort of computer problems have you had?
Hardware components failing, software crashing, file corruption, lockups (especially on my older machines), all sorts of other things
How often do you have them?
Every once in awhile, completely at random.
Do you try to fix them yourself, or pay a computer shop to sort it out for you?
I fix all my computer problems if I can. (I am A+ certified, since November 2004)
What's the worst that's ever happened?
A lot of worst-case scenarios have happened to me (see below)
I had a new system my family bought for me in the summer of 2002. Needless to say, most of the hardware components failed on it over time, and I had to replace each myself. Those included the processor, memory modules, motherboard, hard drive, and the power supply! I am no longer using that system as my primary system, but as an experimental machine, since nearly everything on it changed.
Also, when fixing software issues on other people's computers (usually those that have been infested with spyware and viruses), many times the systems have been screwed up so bad it either took me days to do, or I had to back up their files and reformat and reinstall everything (usually using the restore discs that came with their computers). (I know, you'll probably tell me I should've used System Restore, but using that hardly ever works out most of the time.)
The desktop computer that I currently use most of the time is from early 2002, (I got it from my dad in 2008, who was running a convenience store at the time, and had put in one of his systems to run the store with instead of the one I ended up getting, which was previously used in the store) and as such, is clearly showing its age. I have upgraded a few components on it (the optical drives, by replacing the DVD-ROM drive that wasn't working properly with a DVD±RW burner, and replacing the original CD-RW drive with a spare DVD-ROM drive I had) I'm hoping to get a new computer soon. Because of this, I have been using my laptop (my most recent machine, from 2008) more often.