Locked out by Vista Administrator

Mum bought herself a new computer and proceeded to destroy it relentlessly by clicking the mouse incessantly and randomly. Mum knows nothing about computers and after many years still hasn't grasped what Windows means. Trouble was inevitable.
Mum caused a number of problems which could be repaired by just rebooting Windows...until she managed to do severe damage to the settings.
I was getting sick of having to go there and fix the problems on her PC.
The mistake was to give her administrator privileges on her log-on account.
I thought I'd fix this by changing the account by removing administrator privileges.
Windows then blocked everything that could be done other than just use Windows. No new programs could be installed, no new user could be allowed and everything was blocked by a box asking for the administrator password.
There wasn't any password, never had been a password.
Vista was beginning to really really stink.
I decided to use my own resources and did a Google check for a possible solution. What I found is that many people have come across this very problem but nobody has a simple and easy solution to getting past the administrator password dilemma.
I first thought of trying to re-install Windows but the administrator blocked that idea.
I even attempted a few password cracking solutions but even they were thwarted by the administrator.

What follows is how I managed to bypass administrator without a password:

1. Start PC and press F2 you need to access and modify your BIOS settings and by interrupting the boot sequence should get you to the DOS screen with a list of options
2. If you manage to do this, you will need to select the MODIFY BIOS option and then select the boot sequence to start from the CD drive.
3. You then need to insert your Windows installation CD and reboot PC.
4. If you've done it correctly, the sequence will read the CD and give you the options necessary to re-install Windows. Choose YES and go ahead. 
5. Once Windows is re-installed you can then setup a user account and include administrator privileges and write down the password. 
6. Have the password tattooed on your right hand because you can never be too careful