Windows Won't Start Up: The Monitor is Going to Sleep

By Dan Stone

Blank screens are among the last things you want to see when starting a computer.
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A computer monitor that goes straight to sleep mode when turning on the system is an indication of a hardware problem that may require component replacement. The tell-tale signs that the computer is having startup problems are when the monitor turns on like normal and the activity light displays its active color before turning to its sleep color a few seconds later. The good news is that all the data on the computer is probably safe.

Bad Cables or Connection

A bad HDMI cable won't send a signal to the monitor.
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If you're lucky, the monitor just has a bad cable or a loose connection. Remove both ends of the monitor cable and check for any bent pins or damage to the cable itself; correct any bent pins with a flathead screwdriver and straighten the cable before reconnecting it to the system. If possible, use a different cable to connect the computer and the monitor. Also try using different ports on either side, if available; use a different connection standard if the monitor and computer have another mutual connection type. If the problem is resolved, it was caused by a bad cable or connection.

Bad Monitor

The monitor might be broken if the computer still makes all the normal sounds associated with booting up. If you have another monitor or TV with a compatible port available connect the computer to that monitor and check if the computer works correctly. This also works for troubleshooting faulty screens on laptops that have video-out capabilities. If the other monitor works, the computer's monitor might be blown.

Clear CMOS

A bad BIOS setting could be preventing the computer from sending out a video signal to the monitor. The easiest way to fix this setting is to adjust it within BIOS, but that requires a working screen. You can clear the BIOS settings by disconnecting the computer from all power sources and removing the battery from the motherboard for about five minutes. After the time is up, return the battery to the motherboard, reconnect the power sources and turn the device on. CMOS battery removal requires opening the computer case.

Bad Video Card

The monitor may not be getting any signal because the video card is dead. Some computers have multiple video cards: there may be one built-in to the motherboard and one connected to a peripheral slot. Connect the monitor to the other video card and boot the system: if the computer has only one video card, swap out or add a peripheral video card to the system and turn it on. If the secondary or alternative video card works, the previously used video card is probably broken.

Bad Motherboard, CPU or RAM

The blank screen can also be caused by a bad motherboard, CPU or RAM. A computer won't load at all if the memory is bad. If the computer has more than one RAM module, boot up the computer with one in at a time. Otherwise, try using a different RAM slot or different RAM module. If all other components are ruled out, the screen is going straight to sleep mode because either the motherboard or CPU is broken -- discerning the cause between the two is difficult and either one is a system death sentence.