I've never had problems starting cars with 1st gear engaged and using no clutch. When the clutch cable snaps or the clutch wont work, for whatever reason, starting the car comes natural. Sure it might be a bit jumpy at first, but it certainly doesn't stall
I had massive slowdowns on occasion and I found out it was my actual harddrive giving up the ghost. Everything would be fine and then it would just stutter for a few seconds. While it might not be your problem, it could be. Maybe a defrag could help too, who knows.