Black screen after disabling Samsung SSD RAPID mode

[Kees030]

I installed a Samsung 850EVO 250GB SSD (replaced HDD) and did a fresh install of W10Pro. Added some files from my WORKGROUP, installed Samsung Magician and enabled RAPID mode.  Then I couldn't access WORKGROUP anymore.

Disabled RAPID mode and restarted. Got a hardware error STOP message and my PC rebooted after countdown, however the screen remained black. After 0,5-1 minute the power fan started to blow loudly. No beeps.

I tried a BIOS reset, removed the battery for 20 minutes, removed the SSD, tried DisplayPort in stead of internal VGA, replaced memory to no avail. Without memory I'm getting beeps.

Guessing my PC was broke I then tried the SSD in a HP Compaq Pro 6300 SFF. It booted, however I got the same hardware error STOP message and after reboot I got the same problems as with the 8300.

Seems like the BIOS of both PC's got corrupted after the reboot following the STOP message.

Please help recover the BIOS of my PC's? 

[Kees030]

I've found the Windows+B possibility. Unfortunatedly it didn't help.

Anyone please help making my PC's boot again?