Spray bottles are notoriously uncontrollable.
Unfortunately, the Windex solution most likely got inside and caused some damage by shorting out one or more components.
Check the manual for the "cleaning" guidelines. Most cleaning procedures are very specific; e.g., spray the cleaning solution (if any) on the cloth and wipe gently in a certain manner.
If the cleaning was not in accordance with the recommendations then you have caused damage to the TV.
Probably not worth the effort or cost to try to repair as the TV is 7 years old.