just in case it serves others :
get your Bios date from the POST screen or use free tools like speccy to get it, or type "systeminfo" at the command line prompt and check the results for the BIOS part (bios vendor and bios date).
If you can use windows, set the system date to your bios date, at a time inside the day (say 00:00:00 or 12:00 AM for example). Now reboot and press F2 to access BIOS.
Enter directly your password derived from your Bios date as stated here : https://pastebin.com/L3c3rySj
Note some PCs require to enter a wrong password first then the display changes from "password" to "rescue password".
Enter your password as you would on a QWERTY keyboard : it means for example that
1-9 &0 are on the 2nd row under F1-F11 without pressing shift,
3rd row begins with Tab,QWERTY
4th row letters begin with ASDFGHJKL
5th row letters begin ZXCVBNM
When password is OK, the current date being the BIOS date, BIOS panel opens.
Then go to "security" menu and set an empty password for Administrator an user.
Returned message should read "password uninstalled" or something similar.
Next time , F2 will not ask for anything if Admin password was correctly blanked out.
This worked for me for an ASUS X73S having a BIOS date somewhere in january 2009.
Hope it helps any further reader to get some old ASUS back to use.