Older version of MS Excel were restricted to 65536 rows per worksheet.
Excell 2007 brings some good news to this restriction - the number of rows is larger by about 16 times - summing up to 1,048,576 rows.
Have a look yourself, open a new worksheet, and click: Ctrl+Arrow down. This will make the active cell jump to the bottom of the worksheet, resting in the last row.
Bypassing/Extending Excel Row Limit
There is no easy or effective way of extending the number of rows beyond the limit. Most people would recommend you in case there is such a need, to move you data to a database program, such as "Access" or "SQL" which are limited only by the computer's memory and disk space.
Restricting the number of rows in the worksheet
You can not restrict the number of rows, but rather hide the unwanted rows.
In case you wish for example to have a worksheet of 100 rows only, select row number 101 by clicking its heading number, and press Ctrl+shift+Arrow down (this will select all the way to the last row). Now right click inside the selected area, and choose "Hide".
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