Car Alarms: Alarm no longer works, valet mode, nissan frontier

I have a 2002 Nissan Frontier.  I do not know if my alarm system is factory or not. It has a fob that is separate from the key. Neither says Nissan on them. Fob operated door locks and alarm perfectly until I decided to play a joke on someone and set and disarm the alarm about three times quickly. smart huh! Well now the alarm will not set. The door locks work fine with the fob, but alarm does not. The led is lit up but not flashing when the engine is off and off when the engine is running. The panic alarm works fine. When the doors are locked with the fob the horn beeps once instead of twice like  it used to. When the doors are unlocked there is no horn beep instead of the two beeps I used to hear. Can you help? thanks5

valet switches
valet switches  
It's after market and you put it into override/valet mode.
Sould be no problem getting out of it.

Look under the dash for a smallish button or toggle
switch, usually to the left leg area and then
try, key on just before cranking,
press and hold in the button for up to
5 seconds or, until you get a response from
your siren, & lights.

Then key off. This should be reset.
Try to start it.

If it's a toggle type switch found,
key on, flip switch in opposite direction,
key off. This would be override.
Try and start the car.

Repeat these steps to go back into
override mode again when ready.

Good luck.