there's a third party program that can do this.

i found it some time ago on majorgeeks.com but it might be on other software sites also.
the name of the program was. " Push The Bloomin' Button "

not sure if it is still working in xp pro or vista but it will handle the clicking of the buttons for you once you get it set up.

This has been requested many times as many would like to leave this type of processes running overnight or while away from the PC. I really hope that this gets implemented in the future as this is really frustrating for those with large libraries and/or slow PC's.

I've hit this a few times. I select a large collection of music and hit choose to analyze volume. I walk away because this is fairly CPU intensive and can take some time. I come back to find that the 3rd track has DRM or corrupt and can't be analyzed and nothing else has been done. I really wish this message was queued up and a list of files that were not analyzed would be listed at the end of the operation.

As a bare minimum a selection of "Ignore All", so that after I get it once I can be assured that everything else is going to be analyzed.