Is there a service or process that occurs when a folder is clicked open?

I have one folder on one of my partitions that has a number of subfolders and files totalling around 200,000 in all. Whenever I click on this folder to open it, the system hangs and waits anywhere from 30 seconds (if nothing else is running) to several minutes.

I have 256mb RAM and no other folder causes this problem.
I have turned off a number of services and also turned off file indexing for the entire disc.

Microsoft, as usual, has nothing to say on this issue.

Anybody?

Thanks

Wengang