T1650: UEFI + Secure Boot enabled: Cannot boot anymore

Try disabling Secure Boot in BIOS...

If I could access BIOS to disable Secure Boot, then I wouldn't have posted here. Since the monitor goes into power saving mode, I cannot access BIOS, cannot boot OS, nothing. PC plays dead.

I did everything as recommended by you! :-)

1. Power off and unplug
2. Press/hold power button for ~15 sec
3. Open case and remove motherboard battery
4. Press/hold power button for ~30 sec
5. Reinstall the battery (right-side-up!)
6. No success!

Tried also the jumper option as described here, without success.

According to some folks CMOS clearing doesn't help when secure boot is enabled, so it probably remains activated. Took the NVS 300 out, hoped to get monitor picture using the built-in VGA slot. Without success: The built-in VGA slot is disabled on T1650. ;-)

I assume, that the Nvidia NVS 300 is not compatible with UEFI + Secure Boot. I probably just need an UEFI (Secure Boot) compatible graphics adapter.

A Secure Boot configuration should not stop you from booting into the bios.  It would not allow a boot into an OS but should give you some type of message regarding resetting the Bios options.  But your system is a Workstation so it may be set up differently or the Bios is set up differently.  I ran a GTX 680 on a Secure Boot Asus system before the card got its updated firmware and I had no problem getting into the bios to remove the Secure Boot option.

The Bios update you just did has a comment about an update for incompatible add-in graphics cards.  Perhaps that change is causing the problem.  Your card is Win 10 supported but no mention is made as to its Secure Boot State.

I assume your system does not have the Intel 4000 graphics available.  It should depend on which processor you are using if the system was capable.  The VGA slot is the only one you have on the mainboard and removing the add-in card makes no difference?

Do you have another monitor or an adapter so you could run the signal to a TV?

Have you checked the power LED error codes when powering the system on? See page 45 in the manual.

There are 2 onboard DisplayPort and 1 onboard VGA video ports in this system. And you have to remove the add-in video card in order to test any of them because the add-in video card disables the onboard video ports.

Just wanted to offer a solution on this:

I had the exact same issue a couple of days and I nearly went into depression thinking that i lost a perfectly good PC (out of warranty T1650).

The power LED codes showed normal. I went through all the other CMOS/BIOS reset procedures. The combination of the jumper method and the battery method seems to work (based on some bootup behavior: I had changed bios settings to boot up directly on AC power on, which seemed to revert to default after the cmos/bios reset) but it would still not reset the UEFI/Secure boot settings so still could not see anything on the monitor.

Issue is that my T1650 has the xeon processor which does not have integrated graphics, so the on-board VGA port will not work. But the actual issue is indeed the graphics card (Nvidia NVS 300) not compatible with UEFI and/or Secure boot. I had a new Precision 5810 factory setup with UEFI and Secure Boot (need to check about the secure boot part) and I used the graphics card from the new PC (AMD FirePro™ W4100 2GB) in the T1650 and I could see the bootup attempt on the monitor and could go into BIOS settings and disable UEFI/Secure Boot and everything went back to normal.

Hope this helps someone with this issue.