Why won't my computer screen turn on sometimes?

My computer wont turn on it just has a black screen,it has a little blinking bar at the top left of the screen?

• when i turn it on i can hear the fan and everything but it wont go to where i log in my user it says press DELETE or TAB for bios message or something like that but then after it just goes to a blank black screen and a little white bar at the top left of the screen blinks but nothing happens

• Answer:

  Hello I will do my best to assist you. First of all don't panic, a blinking bar is better than a plain black screen, but it can still be any number of things, here are few common reasons for a blank screen with a blinking cursor: -Corrupt software, malfunctioning soft, or Malware. -Damaged boot up, the computer not knowing where to boot to. -Incorrect shut down. -Sleep mode error. -First- Make sure no USB devices or discs are connected/in your computer. These can halt startup as your computer will try to boot from disc or hardware before normal boot up depending on which options are set, If you did not have a USB device connected or disc inside.... -Next Try- Try starting your computer in safe mode. Simply start your computer and hit either the F2, Del, or sometimes the F10 key on the keyboard. Then try a clean boot...Start, Shut down, and then turn the computer on...If the problem persists, try changing your power saving settings in the control panel. If that did not work -Try This- This is slightly more complicated but nothing to worry about. We are going to go into your BIOS (Basic Input operating System) this is what loads before your operating system is installed. We are just going to change the Boot order so that we make sure your computer is booting up correctly. To get into the BIOS It will usually say “To enter setup press……" This is commonly F3 or F9 or Delete or something similar. If you miss this screen you will have to boot again. Next step once your in BIOS, You should see boot on the top menu, then select boot device priority make CD or DVD the top priority...You should see instructions on how to do this in the bottom corner. *Note: Do not change anything else in BIOS if you are not sure about what you are doing. -If all that did not work- Go in BIOS (some systems have an option on startup as well) and select a system restore or system default settings to revert your computer back to its original form. And my last bit of advise is acquire a operating system disc and reformat your computer if nothing else works. I hope we have solved your problem, if not feel free to contact me on my profile or website for further assistance.