GST Chrono 3707 problem

Hi all,
First time post here, so I appreciate any help that can be offered.
I have a GST Chrono which is around 13 years old. It has not been worn for quite a while (probably a little over 6 months) and I have come to use it today and the chronograph appears to be broken.
The little second hand sweeps fine and the time and date functions appear to all work ok, but the large sweep second hand and 2 small chrono hands don't move regardless of pressing either the start or reset button. The large sweep second hand is at the '75' position and the 2 smaller dials are stuck at around a 45 degree angle.
What has happened? Help!
Is this an expensive fix or common problem?
Thank you in advance for any words of wisdom.
Neil

I own the same watch and mine has been functioning perfectly for years and years but had a service about 3 years ago.

This is certainly not a common problem as the movement is very robust and reliable.

To better understand your problem we need more information.
1. Was it functioning properly 6 months ago?
2. How much power have you given the watch? Maybe not enough wind to make the chronograph work?
3. Maybe it's just time for a service after many years of neglect and the lubricants have dried out.
4. Tell me about the history of the watch. Did you receive it in this condition.....?