After years of idle curiosity, I finally found out what the "Scroll Lock" key on my keyboard does.
For the most part, it does nothing. However, in a few select programs it actually changes the behavior of the up/down arrow keys and the page-up/page-down keys, the most common (these days possibly the only?) program being Excel.
In Excel, with Scroll Lock disabled (the default), the up/down keys change which cell on the screen is highlighted. If you
enable Scroll Lock, then the up/down keys don't change which cell is highlighted, but instead scroll the entire screen up and down.
Just thought you might like to know...
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tanstaafl.