my laptop wont boot, the screen is black for 30 seconds then turns off

[Bendik Aune]

This happened after i changed something in the bios. Ive had someone try to repair it but they didnt know what was wrong with it. They removed the cmos to reset the bios but it didnt work. And know i have no idea how to fix it. Anyone who know what the cause could be?

 

[Bendik Aune]

the fans are spinning rn, and it takes a while b4 i turns itself off, is it fixing itself? should i connect to external display?
edit:so i dont get any display, which means i can do nothing? help would be useful

 

[rgd1101]

MERGED QUESTION
Question from Bendik Aune : "changed bios, laptop screen black for 30 secs then turns off"

Hey. I changed something in my laptops bios and now the screen turns black for 30 seconds, then shuts off. I had someone check it out, they removed the cmos battery to reset the bios, but it didnt work. There werent any problems with the laptop earlier b4 i changed the bios. Does anyone have any idea whats the cause of this problem?It makes no sound when turned on, the fans dont start. So im out of options.

Can you boot into the BIOS again? If you can, may check the boot device setting, make sure the 1st boot device is from the HDD with the OS. But if you can't boot into the BIOS at all, and the problem maybe from something else.

im going to try once i get it back.

 

[Homayoon]

You must remove battery and turning on and press and hold Alt+CTRL+Del for 10 s, then you heard a shout beep and next it solved. you can boot it and continue

 

[Pink Fluffy Unicorns]

You must remove battery and turning on and press and hold Alt+CTRL+Del for 10 s, then you heard a shout beep and next it solved. you can boot it and continue

How can you turn it on when you remove the battery?