Hi @sanos
Try a full power refresh in case it is a corrupted BIOS and check if that resolves the problem.
Here’s the procedure:
a). Disconnect the charger from the laptop if connected.
b). Disconnect the main battery from the motherboard.
c). Disconnect the RTC (Real Time Clock) battery from the motherboard.
Here’s the [link|https://dl.dell.com/topicspdf/latitude-15-5500-laptop_owners-manual_en-us.pdf|service manual] for the laptop. Go to p.26 & p.34 to view the procedure to remove the main battery and the RTC battery respectively.
When the RTC battery is removed measure its voltage. If it is <2.6V DC replace it. Search online for 44YK6 to find suppliers that suit you best.
d.) Reconnect the RTC battery (or its replacement).
e). Reconnect the main battery and re-assemble the laptop.
f.) When the laptop is completely re-assembled, connect the charger and try to turn on the laptop.
If it starts OK there may be a message about the date and time being incorrect. This is normal as the BIOS has been completely reset back to its default settings. Once the date and time have been adjusted the message won’t appear the next time that the laptop is started.
If you had previously changed any user defined settings in BIOS to suit whatever specific hardware configuration that you had for the laptop, then these will have to be set again.