Hey, I've this problem on my HP laptop: when I turn on my engine, it work well until the part before choose the session (write the password) ... And at that part, it stay on "Wait" infinitely. I had this problem when I had the message "Microsoft stopped running" and I had to turn off and on the laptop.
Either win problem, or hard disk failure ... Though windows don't crash for no reason, so it may be HD failure ... Happened to me last month, lost everything with it ...
Turning on a laptop is also known as booting. There are no engines in a laptop. Your windows has probably been corrupted. Try an external boot disk to boot up and back up the data. Then, reinstall Windows in a separate partition of its own so that the next time this happens, you can just format that sector and reinstall it without fear of data corruption.
Windows will crash if the boot sector of your hdd is corrupted. This can be due to software or hardware failure.
If you are not tech savvy, I recommend taking your laptop to a professional and have him/her help you. If you try to do it yourself and mess it up, it will be difficult to recover.
not enough HP ... go get some HP potion Seriously, safe mode is your best choice or reinstall windows. To enter safe mode you need to press F1-F11 button (not sure which one exactly as it varies from PC to PC). If either of those 2 options don't work then you better spend some cash for repairs or a new laptop.
Try pressing escape repeatedly during boot. If you need to backup data from your laptop you could always use ubuntu usb stick.
You can boot from a usb drive that has a portable OS in it. Search in Google for more info. I would really recommend you to research everything before attempting anything.