I think Mr. ed is trying to get to the Windows desktop via "safe mode" in order to reset or remove the long forgotten administrative password.
I am pretty sure that you can not bypass the administrative password by booting to the "safe mode", safe mode most likely WILL require THE PASSWORD in order to get to the safe mode desktop.
OP does not need to access the BIOS which most computers will use F2, F10 or DEL key at bootup POST...
The only solutions I can think of is removing the HD, connecting it to another Windows PC via a external USB to HD adapter then running one of those password crackers on it..
Personally I would simply put in the Windows XP CD and blast the existing installation (provided you do not have any important "data" you want to salvage) with a fresh install.. SKIPPING the password portion at the installation time..
For home usage, having an administrative password is really an optional item. Not having a password on the administrative account does open up SOME "vulnerabilities" to malware or virus.
However if the administrative account is the ONLY account on the PC there is NO DIFFERENCE in risk since you have full administrative privileges any malware/virus will have THE SAME full access/privileges of administrator.
The only way a password can reduce the risk is to create a second account with LIMITED access/privileges and YOU ALWAYS use the second account..
Not many people will do this since to install or make changes to software and settings on a limited account you WILL be prompted for the administrator account name and password. In other words a royal pain in the place sun doesn't shine..