Vista - Why are handle counts going up in a .NET application?

Hello,

We have a .NET application that runs as a service. Our customers have
observed, using Task Manager, that handle counts are going up after a period
of time and claim it is a leak on our part.

I have scoured the code looking for anything that I am not closing or
disposing, but don't see anything. I ran two different profiling tools and
also put in my own logging to make sure that at least at my level (in C#) I
do my part by making sure resources don't leak. My logs are steady after
days of running.

The only resources that I use are: Sockets, Threads, Files, and Timers - as
far as I can tell.

Are there resources that .NET runtime allocates on my behalf? ( I do know
about the System Thread pool )

Or is there a known handle leak in .NET that I am not aware of?

Thanks, any help on this will be greatly appreciated!