Well after months of frustration, I finally figured out what the problems was with those inconsistent and hanging startups on my Toshiba laptop.

No one will believe this solution, but it did the trick and hasn't hung once since finding the problem.

I blew very hard into the opening where the hot air from the heat sync on the CPU is blown out by the fan. A pile of dust blew out. I then put a vacuum on the opening and sucked out any residual dust. Presto no more problems and the machine runs much cooler as well.

Toshiba ought to put this in their maintenance/user manuals even though it sounds odd.

An ever better solution would be to use those cans of compressed air which are sold in a lot of computer stores.

A regular burst shot into the opening would probably do the trick as well and prevent future problems.