hi i had the same problem with my vectra about two years ago, i would try to start it and it would wind and wind almost till the battery was flat. it turned out to be the rubber pipes on the injectors which drain the diesel back to the tank which is not required. when they get old they get pourous and so allow the fuel to drain right back.to change the pipes is easy and costs about £4.00 for a length of pipe from a local car diy shop, simply cut it to the lenght of the old ones and change them. turn the engine over until it starts it will be ok after that.
Hope this helps
Trev
April 2007