Yes.
You can set individual cells / rows / columns with
protection, leaving the rest of the sheet without.
Select all the rows (click on the row number at the side
of the page) that you DON'T want to protect, and then
click Format->Cells->Protection and un-check the "Locked"
button.
Now, select Tools->Protection->Protect Sheet, and type in
your password, and voila: all the rows you want protected
will be, with the rest of the rows still available for
editing.
Alternatively (as you may have many dispersed rows you
wish to lock, in which case the above method will take
longer), you could select the whole workbook (click on the
rectangle to the left of the "A" column and above Row "1",
then select Format->Cells->Protection and uncheck the
Locked button. Then select the rows you want to lock, and
then go into Format->Cells->Protection again and re-check
the "Locked" button to lock these cells. Then protect
your sheet.
Happy to help,
Gary Thomson