First of all, the best place to ask technical support questions would be the Technical Q&A forum.
https://www.techrepublic.com.com/5221-6239-0.html
You would also nee dot offer some basic info.
Is it the BIOS password that you can't get past?
Of the Windows administrator login?
If so,what operating system is it?
IBM does havae a FEW default passwords, but for the most part it is a protected motherboard where the code is in the chipset and can only be changed by either IBM or a system board replacement.
Tech Q&A with some more information is your best bet though.
Some default passords depending on BIOS type, but manufacturer BIOS and security changes will usually overwrite them.
http://labmice.techtarget.com/articles/BIOS_hack.htm
How to get around the administrator password:
http://www.petri.co.il/forgot_administrator_password.htm
Good luck,
OM