I am not suree why I got ur invitation. Last time I played with iis is for camouflaging my nginx with iis default page for fun. Guess what, I can find log entries there that some miscellaneous scripts thought it is a windows web server with iis...
Anyway, I think I found answer for ur question
http://stackoverflow.com/questions/10863059/iis-web-application-hangs-periodically-needs-system-reboot