We're sorry about the trouble with Lightroom. Could you please help us with the version of Lightroom you're using?
In order to find your installed set of brushes, make sure you're in Develop module. please go to preferences>Preset tab> there make sure "store preset with this catalog " is unchecked then click on show all other lightrooms preset.
A new window will pop up, open the Lightroom folder then open the Local adjustment presets folder where you'll find all your brushes installed.
If brushes are there, click on okay and then on the right-hand side under the brushes click on the tiny arrows, you'll see your brushes there.