There have been several previous tips about how Internet Information Server “holds onto” DLLs that you use in your ASP pages. It turns out there is a much easier way to unload them so you can recompile them. On the Home Directory tab of the Properties for your web site, the Application Settings section allows you to set permissions and whether the site runs in the same process space or in a separate space. If there are DLLs loaded for this particular site (regardless of which process space you choose), the Unload button will be available and enabled. Click that and the DLLs will be unloaded, and consequently, unlocked by the system. On occasion, it may take a few seconds for NT to release the lock, but it’s normally pretty quick.
If you have to do this on a live site, be sure to stop the site before hitting the Unload button. If you don’t, you run the risk of someone else hitting the site, invoking your objects, which would lock them up again. Stopping the site prevents people from hitting the site while you get the objects updated.