Is it possible using SQL in an SQLite table to replace part of a string?
For example, I have a table where one of the fields holds the path
You can use the built in replace() function to perform a string replace in a query.
Other string manipulation functions (and more) are detailed in the SQLite core functions list
The following should point you in the right direction.
UPDATE table SET field = replace( field, 'C:\afolder\', 'C:\anewfolder\' ) WHERE field LIKE 'C:\afolder\%';