I want to share the solution.

Issue: QTP 9.0 stopped Responding

Solution 1 did not work:
Uninstall from Start=>Programs=>QuickTest Professional
Install same version but problem still exists

Solution 2 did work:
Downloaded “QTPCleanUninstallerV2.10.exe” and executed .exe
Click on Start Scan then clicked on Clean Registry then restarted my PC
Install QTP 9.0 and problem solved.

Thank you Tarun for time saver utility.