I have a desktop with windows 7 ultimate installed. Whenever I shut it down from the start button. The text that says that it is logging off and shutting down is present and the monitor blacks out and says no signal. But the lights in the RAM is still on and all the fans in the desktop is still spinning. Why is that? It seems like its not shutting down completely. I have also got disk problems lately. Event id 175 and 50. Which I think is caused by the computer not shutting down completely. How do I troubleshoot this one? Feel free to ask if you need more details, thanks.
It sounds to me like your shutdown button is set to sleep which will keep enough power to keep your system state in RAM. A fan will remain running as well. Check your power options to be sure that when you press the shutdown button it's set to actually shut down and not sleep.
Event IDs 175 and 50 seem unrelated at this time, but do indicate poor disk operations. You may want to consider running a SMART diagnostic on all of your disks to look for errors.
EDIT 1: Since the power button in the start menu is confirmed to turn the PC off, check to see what the physical power button on the PC does. Use the same method to find that option and set it to shut down the PC. Then, tap the power button. Do not hold it in. It shold initiate a graceful shutdown. See if the RAM lights are still on and the fans are still running.
Did you test your drives with a SMART testing tool?