I've decided I want to build a retro Windows 9x/ XP machine and remembered that my dad still has his old Advent 7016 laptop.

The laptop was running fine when put in a cupboard 10+ years ago.

The battery has been replaced at some point and looks in good condition (not bloated). It seems to hold charge after leaving it plugged in overnight.

The CMOS battery was dead with a measure 1.8v so I replaced it with a fresh cr2032 at 3v.

So the laptop turns on, fans spin at full speed, HDD seems to be spinning but nothing happens. No HDD indicator light and no display. It's not just a black screen, the display backlight doesn't turn on.

I've tried tearing down the laptop but found nothing. Everything seems to be in fair condition other than needing some thermal paste.

I saw a YouTube video repairing old GPUs and they found that the BIOS chips had corrupted over time. I wonder if this could be the fault here but I have no way to flash a new BIOS as no instructions, no BIOS files etc. The BIOS chip is socketed.

The laptop is as follows:
Pentium 4 2.66ghz (Northwood) socket 468
2 x 256MB SODIMM modules
ATI Radeon Mobility 9000 64MB
Sis soundcard
1024x768 display

Any help would be greatly appreciated.