You shouldn't lose the but
just in case, you should sync them with your Google Account. To do this, click the little spanner in the top right corner and from there, navigate to: Options ---> Personal Stuff ---> Sync ---> Set up sync...
You can then sync all of your bookmarks, extensions and user settings to your Google Account. This will be stored online until you need it again.
You should also copy the user settings folder for Google Chrome which can be found at: C:\Users\USERNAME\AppData\Local\Google\Chrome\User Data
There should be a folder called Default
which you should copy to your Desktop. When you have re-installed Chrome, you can then move the folder from your Desktop to the previous directory. The folder will more than likely be hidedn so you may have to enable 'Show All Folders'. Hidden Files and Folders - Show or Hide