TrackMeNow is what I use every day to track my working hours. It is an opinionated spreadsheet designed to stay out of your way and tell what you have done during the day. I have been using it for two years; without it, I feel empty. Download it here.
Adjust your zoom so you see at least up to the F column.
If your Excel is in Spanish, use Ctrl Shift . instead of Ctrl Shift , to add the current time.
When you want to start a new day, simply select the B column and press Delete.
The spreadsheet is protected to avoid showing Excel's green triangles. Go to Tools | Protection | Unprotect Sheet to unprotect it.
I welcome any feedback, just send me a message.