VCI-100SE Deck C/D issues (URGENT HELP NEEDED)

Hi All....I am in desperate need of some help!!

I am using a Vci100se with tsi file 2_5Tpro 1.2.tsi and tracktor pro (1.2.2 I believe) i know its a old style set up but its always worked perfect for my style of mixing up till now.
i haven't made any changes to my settings or anything major on the pc but for some unknown reason the decks C/D keep activating themselves and i lose controll of decks A/B the only way to regain controll of A&B is to quickly turn the C/D knob a full turn to the right and then back to the left.
I have tried to disable all other deck views in the settings so that i am only left with the 2deck int mixer but it makes no difference. i have also tried reinstalling the TSi file and again no luck. I have taken the VCI apart and made sure the inside is as clean as possible (i previously had a simular issue with the crossfader and this seemed to fix the problem) but again no luck.

Please please please can someone throw some light on what the solution might be. I'm supposed to be proforming at the weekend but don't know if i will be able to unless i get this fixed,

Many thanks in advance,

Babbel