When I start my computer and it comes to users

Hello.

When you created that password, you should have had a security question answered that would help you remember what the password is exactly. Even though you wrote it, remember that it is case sensitive. So if your password was

SystemShock2 it won't respond to systemshock2 or SYSTEMSHOCK2, or anything that isn't exactly as it was written.

If you cannot get in, reboot and keep pressing F8 until you get the safe mode options. Log on as Administrator and change the user account password, or remove it entirely.