I've got news for you Jim. I've had three updates that
have crashed my computer. (Though never a service pack.)

ALWAYS backup before installing ANYTHING. ALWAYS backup
anything important. These are the most basic rules of
using any computer. Not backing up is like not fastening
your seatbelt or jumping out of a plane without a
parachute.

Software goes wrong, disks crash, users make mistakes,
computers get stolen or hacked.

BACKUP ANYTHING IMPORTANT!!!!!!

don't want to know how our TV works either.

I'll bet you know that you shouldn't stick your tongue
inside it. Backing up your data is about the same as
that.