With most desktop PC's there is a simple way of resetting CMOS and clearing password. Read the motherboard manual for instructions .
(usually disconnect mains power cable and move jumper on motherboard to clear.)
(There is a risk of static damage and changing critical cmos settings)
With business class laptops by major manufacturers such as Toshiba, Dell, HP etc the password is stored in a eprom or similar chip
special software only available to main dealers/authorised computer repair shops is required. (model specific)
They should ask for proof of ownership before helping .
If it is a laptop hard drive password, very few companies can clear it without erasing all data on the hard disk. (so expensive)