Question: Flashing/blinking underline on screen
Question: Flashing/blinking underline on screen
Hello everyone!
I recently attempted to modify something in my BIOS, but it didn’t go as planned.
Every time I power on the computer, right after the boot beep appears a white flashing line on the screen, and the display also starts flashing, eventually going completely black when the underscore disappears and fades slightly when it reappears.
I’m unable to access the BIOS or see the motherboard screen during startup.
What I’ve tried so far:
- Pressing the DEL key at startup (repeated many times)
- Pressing F keys at startup
- Leaving only one SSD connected
- Removing all HDDs and SSDs
- Deleting all RAM modules, leaving just one (tried multiple slots)
- Re-seating power cables
- Unplugging the power cord and pressing the power button for 30 seconds
- Resetting CMOS (took it out for 10 minutes)
- Shorting the pins to reset CMOS
(All these steps either led to a boot without a beep or immediately caused the same issue, with no BIOS access)
I’ve also tested using HDMI and DVI ports with different screens, tried two different keyboards.
Anyone have suggestions on how to fix this?
Thanks in advance!
GA z87 HD3
i7 4790
Cooler master hyper Fan
2 system fans
1 Crucial 1600mhz DDR3 4gb ram
SSD Crucial 250 gb
650 watt cooler master PSU
I have been using this setup as a hackintosh for years, attempting an OS update. I found a guide suggesting disabling secure boot and setting memory to 64MB, plus turning off the serial port. However, the issue began before these changes. Now it constantly stops at the underscore, appearing roughly one-third of the time.
One potential suspect is the PSU. How old is "many years"?
To investigate further, examine Reliability History/Monitor and Event Viewer for error codes, warnings, and informational events linked to the issues.
Another step involves shutting down the system, unplugging it, and opening the case. Remove dust and debris, then check that all connections, cards, RAM, jumpers, and case parts are securely in place.
Use a bright flashlight to inspect for any signs of damage.
Finally, run "dism" and "sfc /scannow" to detect and resolve any problems.
Refer to the motherboard's User Guide/Manual to confirm these actions are performed correctly.
Incorrect boot configuration. Likely the operating system is set to UEFI, but the system attempts to boot using legacy mode. Alternatively, the OS might be in legacy mode while trying to boot in UEFI. After repeated failures, the system should automatically switch to BIOS. Clear the CMOS jumper with CLEAR_CMOS and begin using a single RAM module. Enter BIOS settings and adjust boot mode preferences. Ensure fast boot is turned off and secure boot is disabled.
I performed several CMOS resets using the jumper, removed the battery for more than an hour, and now it appears to reset to default settings because it restarts immediately upon powering on but still shows a flashing underscore, preventing access to BIOS. I also tested another CPU i3 4330 with the same socket and HD4600 graphics as my i7 4790. I've tried various RAM modules and different slots, but nothing worked.
PSU is precisely what I was expecting—it's been over 5/7 years. I'm having trouble accessing anything; the underscore keeps appearing. No keyboard keys are responding. I've tried several different ones.
When you reach the blinking underscore, it's too late to enter BIOS.
The process of loading the OS from HDD/SSD has already begun.
After pressing the power button, keep pressing the DEL key continuously.
You might also disconnect the OS drive, which will prevent the OS from loading.
I've been testing everything with just one RAM module and various slots. CPU, fans, and that's about it. No luck.
So I don't have any HDDs or SSDs connected either.
And honestly, I'm pressing that key a lot.