I installed Crystal Reports on my Plesk 7.5.3 server, and after a reboot that was required for the installation, Plesk and all our customer web sites stopped working. I get the following error in the event log every two minutes: A process serving application pool 'plesk(default)(pool)' failed to respond to a ping. The process id was '2288'. There appears to be a related event a few seconds after this one, namely: Application popup: Warning : Unknown(): Unable to load dynamic library 'C:\Program Files\SWsoft\Plesk\Additional\Php\extensions\php_curl.dll' - The operating system cannot run Warning. As a precaution to having many unhappy clients I removed Crystal Report to see what happens. BUT THE PROBLEM IS STILL THERE! Does anyone have experience with this problem?