Sparkrite Alarm faulty?

When i bought my car, the previous owner had fitted a Sparkrite SR85 car alarm, however when i bought the car i did so under the knowledge that it didnt work - the alarm didnt respond to its remote but i wasnt particularly bothered.

Recently the alarm has come back to life with a bit too much vigour. It sets itself off constantly while driving and i have no way of stopping it.

Ive tried disconnecting the power to the unit, however when i do this the car wont start at all, i assumed this was because it was linked in with the starter and as a fail safe, if the power is disonnected the car wouldnt start. I found a users manual for the SR85 however, and it is not equipped with an immobiliser. What can be causing the starter to not engage when the alarm isnt supposed to be linked to it?

The car is a 1996 Reault Clio. It has an immobiliser as standard, however this still allows the starter to turn, but instead wont create a spark, the situation when the power is disconnected from the alarm means nothing at all happenes when i turn the key.