Hi every one

I have some knowledge in computers but I feel my problem is so big , but it might be easy for others.

I have an old Desktop computer with XP OS. I forgot about this computer for more than 4 years , and now i decided to re use in my office.
The main problem that i have is me forgetting my log in password. I saw many video of resetting the password, however all these ways would never work for the following reasons.

1- My Cd drive doesn't work ( this is for people who will tell me for booting solution)

2-When i got the F8 screen , the keyboard gets locked and i can't move the arrow up or down to the safe mode choice ( this is for the safe mode solution) and yes my keyboard works.

3-I tried the administrator user name and blank password and didn't work as well ( this is for ctrl+alt+del solution)

I heard that there a hardware solution where you can take out a small battery and plug it back, and this will reset everything, but I am not sure of that

I hope someone can help

Thanks in Advance