Insomniac Laptop

Problem: When I close my laptop's lid, it goes to sleep mode.
Then it wakes up at night and never goes back to sleep.

I've search myriads of websites most of those only commenting the ethernet adapter.

I've scanned the event viewer for anything suspicious, and everytime the comp wakes up is a different event.

I've been through the hassle of checking all tasks one by one in the task scheduler and disable every behaviour that would wake the comp.

After doing all of that, the problem isn't cured.

The only solution is put the comp to sleep, have the battery disconnected and power wire too.
Why that way? because the wake up is quicker than a full boot. And the disconnected battery isn't that big of a deal since that laptop isn't that mobile.

This is a HP laptop (HDX16 1050) with vista x64 installed.

If anyone found a real cure to that problem, I'd be very pleased to get that solution.

thanks a lot.