Next time when the system is booted, hit the key <F8> during the boot-up. This will cause a menu to appear, retry it if it doesn't appear. When it does it should be a menu, select "safe mode" and allow it to boot. Hopefully, it continues and enters safe mode display. Once there use the "restore point" feature and enter a date before the problem happened. Hopefully, you can recover and all is well. If not, then just got you to this point, some new s/w, or h/w or installed something, recent lightening storm, power glitch, constant or any beeping, please inform if you can. it always helps to know and pass it on.
My computer keeps booting to the blue screen,stops and then reboots,stops and reboots, over and over. need help