It could be the cable itself, the plug on either end of the cable, or one of the sockets the cable plugs into. My instinct would be to leave it; if it happens again you can try to diagnose it down by, say, swapping the cable with a friend or family member to see if the problem moves.
Or if you’re not short of a dime replace the cable - it’s certainly the most likely candidate.
Yes it does. (Not by default, but the setting is available and usually well worth using. I love the Clear Type on my XP system. It can be problematic on a few monitors, however, if it is not further tweaked).