The motherboard part number is not tied to a service tag number.

If this Vostro 5490 was purchased by you directly from Dell, then we might be able to find the service tag number by searching internally for your private Dell Customer number and private Dell order number.

If you did not purchase this Vostro 5490 directly from Dell, then there is not a way to find the service tag number.

@DELL-ChrisM2​ 

Hi,

Thank you for the clarification. I bought this Vostro 5490 from a reseller more than 4 years ago, so I don't have a direct purchase invoice or customer record with Dell. Unfortunately, there is no way for me to retrieve or recuperate the original service tag.

Interestingly, I didn't have this service tag or BIOS issue until very recently, after I found that the battery had become swollen inside the laptop. That incident seems to have coincided with the tag data being wiped or corrupted.

Given that the tag is completely blank/showing as code 0 now, is there any procedure or technician tool to reinitialize or write a service tag back to the motherboard so the system can accept updates and run properly again?

Thank you for your help.

@Tarekdellvostro5490​ 

Yes, factory service can rewrite a service tag, but it sounds like the system has suffered internal damage, so that may not (likely will not) solve the problem.   You're likely in for a system board replacement as well as a battery replacement.