Hello, and Welcome
You can enable the Hidden Administrator Account using a bootable disk. Follow the steps here. Once you have the Administrator Account enabled you can change or delete the password in Control panel under USERS. On a Windows 7 computer you can burn the iso by right clicking and selecting Burn Disk Image. On a XP computer you can use isoburner. It's best not to reset the password. Only enable the Adminstrator account and use that to change or delete the password of your account.
If there is more than one account on the computer, log into the account that does not need a password and type CMD in the search box. Right click > Run as Administrator then type:
net user administrator /active:yes
You can disable the Administrator account again using
net user administrator /active:no