Multithreading attempt Python fail - windows

Question

The following code is an attempt of mine at a voice recognition program. The voice recognition works fine and can understand me, but I encountered a problem at certain points in the program the code would sort of freeze, or hang but without an error.
To get around this I attempted to add a timer using multi-threading which should begin at a = True and after 3 seconds the program would automatically close. If the recognising worked perfectly the a = False should stop the timer before it closed the program. This obviously hasn't worked or I wouldn't be here.
I added a few print statements here and there so I could visually see where the code was when running, and I saw the the code for the timer begins however the code for voice recognition does not.
import speech_recognition as sr
r = sr.Recognizer()
import os, threading, time, sys
import subprocess as sp
print("Voice Recognition Software\n\n***********************************\n")
class myThread (threading.Thread):
def run():
print("Checking")
while True:
if a == True:
if a == False:
continue
for x in range(3):
time.sleep(1)
if a == False:
break
sys.exit()
def program():
while True:
print("voice recog has begun")
r.energy_threshold = 8000
t = None
with sr.Microphone() as source:
print (">")
a = True
audio = r.listen(source)
a = False
try:
a = True
print("Processing...")
t = r.recognize_google(audio)
a = False
print (": " + t)
except sr.UnknownValueError:
print("Unknown input")
continue
except sr.RequestError as e:
print("An error occured at GAPI\nA common cause is lack of internet connection")
continue
if "open" in t:
t = t.replace("open","")
t = t.replace(" ","")
t = t + ".exe"
print (t)
for a,d,f in os.walk("C:\\"):
for files in f:
if files == t.lower() or files == t.capitalize() or files == t.upper():
pat = os.path.join(a,files)
print (pat)
sp.call([pat])
success = True
if success == True:
continue
a = False
success = False
thread1 = myThread.run()
thread2 = myThread.program()
thread1.start()
thread2.start()
EDIT:
I see some mistakes of my own here like indentation of the def function but even after fixing what I see it doesn't work as intended.