Are you using crystal report viewer object on web ?
When you setup crystal report viewer, there's property "PrintMode" and the choise are "Pdf" and "ActiveX".
If you choosed "ActiveX", there's 2 conditions when clicked print button :
1. Popped up window show dan hide.
This happen because your crystal report installation. Uninstall and clean up (delete) folder CrystalReportWebFormViewer2 or 3 (i don't remember for vs 2005) at "c:\inetpub\wwwroot\aspnet_client\system_web\2_0_50727\". Then re-install your crystal report distribution run time.
2. Popped Up dan shown blank window.
This mean, your browser in progress downloading reporting ActiveX. Wait for 1 - 2 minutes and window will prompt for installation. Choose yes, after that you when you click print button, it will show printer dialog.