Assuming you've lost your password to a wordpress installation, but you still have access to your host's panel and/or database, here's how to reset your password:

1. Navigate to the Users Table
2. edit the row containing your username.
3. locate the userpass field
4. Replace with a new password hash using md5()

In Linux,

echo -n NEWPASSWORD | md5sum

In Windows Powershell,

"NEWPASSWORD" | Get-Hash -Algorithm MD5