If it asks for a password
immediately, even before BIOS posts then that would be a BIOS password. To remove that you would need to enter your BIOS and change it to not require a password.
More likely, it is a Windows 7 password like Clifford was explaining. If you go to Control Panel > All Control Panels Items > User Accounts, there you can remove your password if you wish.
If you prefer you can leave the W7 password but set it to log on automatically. See Ian's article
HERE for instructions on how to make it logon to a specific user by default.
Change is always difficult; I was not a huge fan of W7 in the beginning either because I wanted to do everything as I always had in XP and that just isn't possible in W7, but you get used to the differences and start to take advantage of some of the benefits and, in time, it gets easier.