Why don't installing yahoo messenger? - Yahoo Messenger

Reboot your computer.
2. Press Ctrl+Alt+Del on your keyboard. This will bring up the Windows Security window. Click the "Task Manager" button and then click the "Task Manager" tab.
3. You will see a list of files/applications. These are the applications running in the background on your system, whether they show on your taskbar or not. Any one of these applications could be causing a conflict with the Yahoo! Messenger installation.
4. Click the top item on the list to highlight it. Then hold the "Shift" key down and click the last item on the list. This should highlight the whole list.
5. Click the "End Task" button. This will temporarily close all background applications on your system.
6. Click the "X" in the upper right corner to close the Task Manager window.
7. Install Yahoo! Messenger. You should not experience the same issue that you had before.
8. After Yahoo! Messenger is installed,run registry cleaner reginout also reboot your system. All other background applications will return to their original configurations.

Hello premlove23, check first if your PC is infected by a virus. try installing other softwares and see if they install the same. if the installation is denied, your PC is infected.