Boots into Windows, but no video during post

[jakeyakut]

Hi! It's not that of a problem more like concern.

Boots into Windows just fine, everything within Windows is fine, everything works perfectly BUT

While booting, during POST, there is no video output. This doesn't let me get into BIOS.

Also sometimes it just doesn't boot at all. Then after a couple of restarts, boots into Windows just like nothing happened, without video on POST again.

Tried booting without external GPU, HDMI plugged into motherboard - same result. No video, then BOOM - Windows.

Tried to spam DEL while booting - doesn't boot anywhere.

Disassembled and reassembled the whole system into other case (without pcie riser pcb), problem remains.

Don't know BIOS version

HALP!!11!

Windows 10 64 bit

Intel Core i5-6600k, stock frequencies

Asrock z170m-itx/ac (don't judge me i was desperate :D)

2x8Gb DDR4 Corsair Vengeance LPX

1xSSD Samsung 850 Evo 250Gb

2xHDD 1Tb

Zotac GTX 980 AMP!, connected via HDMI

Silverstone SX500-LG 500W

 

Video of Booting the System: 

 

[Crazymarf]

did you try different cables like VGA, dvi or a display-port?

[jakeyakut]

3 minutes ago, Crazymarf said:

did you try different cables like VGA, dvi or a display-port?

nah, but worth a try. Any other ideas, maybe why it does that? thx

[Crazymarf]

Just now, jakeyakut said:

nah, but worth a try. Any other ideas, maybe why it does that? thx

some bioses doesn't see the hdmi screen, i had this problem with a old screen that didn't had HDCP support. And my BIOS didn't detect it until windows was booted up.

 

Or maybe your bios setup has a setting that only outputs to a vga for example. maybe thats the problem.

[TheNuzziNuzz]

Settings. Disable all types of fast boot in the BIOS. Get there by pressing and holding shift while clicking restart in windows.

Also in windows, run "MSconfig" (Winkey-R), then go to the boot tab, and disable "No GUI boot."

[jakeyakut]

9 minutes ago, TheNuzziNuzz said:

Settings. Disable all types of fast boot in the BIOS. Get there by pressing and holding shift while clicking restart in windows.

Also in windows, run "MSconfig" (Winkey-R), then go to the boot tab, and disable "No GUI boot."

No GUI boot was disabled, but couldn't get to bios via shift+restart, pc restarted but no video and nothing

[jakeyakut]

14 minutes ago, Crazymarf said:

some bioses doesn't see the hdmi screen, i had this problem with a old screen that didn't had HDCP support. And my BIOS didn't detect it until windows was booted up.

 

Or maybe your bios setup has a setting that only outputs to a vga for example. maybe thats the problem.

my display is actually pretty old, Acer x233h. But I was able to get into bios with this monitor before

[Crazymarf]

2 minutes ago, jakeyakut said:

my display is actually pretty old, Acer x233h. But I was able to get into bios with this monitor before

that's strange. after a google search, your screen is HDCP compliant so thats is not the problem. Did you already tried using a different cable or even better a different screen?

[jakeyakut]

1 minute ago, Crazymarf said:

that's strange. after a google search, your screen is HDCP compliant so thats is not the problem. Did you already tried using a different cable or even better a different screen?

unfortunately, don't have any other cable laying around. have a different screen tho, give me a minute

[jakeyakut]

9 minutes ago, Crazymarf said:

that's strange. after a google search, your screen is HDCP compliant so thats is not the problem. Did you already tried using a different cable or even better a different screen?

tried different monitor successful boot into bios, showed post and everything. the resolution was 1024x768 tho, fast boot disabled

[Crazymarf]

1 minute ago, jakeyakut said:

tried different monitor successful boot into bios, showed post and everything. the resolution was 1024x768 tho, fast boot disabled

for the low resolution that's normal for some bioses. but still I find that it is very strange that a different monitor is working...

is this screen connected to HDMI?

[jakeyakut]

1 minute ago, Crazymarf said:

for the low resolution that's normal for some bioses. but still I find that it is very strange that a different monitor is working...

is this screen connected to HDMI?

same cable same port even the power cable is the same. uefi supports full hd and previously posted in 1080p. now it posts in 768p and switches to 1080p in windows. strange

[Crazymarf]

1 minute ago, jakeyakut said:

same cable same port even the power cable is the same. uefi supports full hd and previously posted in 1080p. now it posts in 768p and switches to 1080p in windows. strange

indeed. i suggest you double check the settings in your bios. or even restore it to the defaults.

[jakeyakut]

5 minutes ago, Crazymarf said:

indeed. i suggest you double check the settings in your bios. or even restore it to the defaults.

oh, forgot to do so, but thanks for other display idea! at least i have an access to uefi if something happens

[Crazymarf]

4 minutes ago, jakeyakut said:

oh, forgot to do so, but thanks for other display idea! at least i have an access to uefi if something happens

You're welcome

[jakeyakut]

Just found out what caused the problem!

CSM(Compatibility Support Module) was enabled by default, i am not sure why, but it should be disabled!