What exactly were these things you did when you originally woke up it from sleep mode, Since this never happened before you woke it up that one time, Its safe to assume that maybe something you did after waking it, is hte cause of all this. If not another question that comes up is, How long was it in sleep mode for? Not really an essential question but it may in fact help out who knows
Have you tried safe mode? or can you even get as far as to choose that option?
In all honesty, seems almost like a harddrive issue, but at the same time the keyboard/mouse thing leads it to be a motherboard issue as well
could be dealing with something easily solved here, Or extremely difficult
Have you tried starting up without your keyboard plugged in, to see if it recognizes that it isn't there, Have you tried this with your mouse as well? just a couple of ideas,
Do you have your xp cd somewhere nearby incase you need to fully reinstall?
, Its a not so fun thing to do but the possibility is always there