Dr. Watson, the system failure or "crash" analysis tool, has been replaced in Vista with Problem Reports and Solutions. Dr Watson is available in xp...great tool to use i used it many a time when i ran xp LOL....yes i tinker alot with my comps.

i would say its a ram issue....so get that checked out....laptop RAM is easy to fix it could even be as simple as the ram is loose in the slot.

Find out where your RAM is stored..its usually on the bottom with a pop off door and see if the RAM is inserted if it is then it maybe time to replace the ram...if you have two sticks of ram then take one out and turn on the machine and if you can get into windows you know the RAM stick you took out was faulty.

Hope that helps