Administrator account password

[cm2968]

Hello,
 
I have a Sony Vaio VGN-AW41ZF model. have been using it for several years. It works seamlessly with Windows 7 Home Premium pre-installed.
 
I have used with a standard user account but now need to access the administrator account. It turns out I forgot my password. I've tried all the passwords that can remember without success.
 
When I turn on my VAIO it asks me the BIOS password (which fortunately still remember) then appears the Windows 7 accounts menu to choose which account to use. My standard user account is working well. I can enter and work with the VAIO. If I want to get into my administrator account then I can not because I forgot my password.
 
Is there any way to reset my Administrator account?
 
Grateful in advance for any help,
Carlos