plzz folow this step to solve your problem
Check your webcam hardware here using different software - Hit "allow" in the top window and check the result in the left panel. If you have a reasonable result,move on.http://www.testmycam.com/
When you come to test your cam in Yahoo later - if you have a blank box - you will know the A4 software failed to load properly.
Configure webcam to Yahoo Messenger.
It's good practice to disconnect and re-connect your webcam before you start - if you have been using it elsewhere the Yahoo software may have difficulty in locating it. Mine, I just unplug it from the USB and plug it back in, if yours is integral with the computer you will have to re-start the computer, unless the software has a feature for this.
Of all the chat programs, Yahoo is the most painful software to set up but if you follow these instructions you should be ok.
Open messenger - on top toolbar. Left click ( > ) Messenger > Preferences > Connection - Select 'no proxies' or 'connect direct to the internet' depending on the version of messenger you have
make sure your internet connection and country are correct in the lower two boxes > Apply > OK
> Messenger > My webcam - the warning panel will launch, click 'OK' and your webcam will start. You should be rewarded at this stage with your happy smiling face. ( If not abort configuration and re-load A4 software )
With webcam still running > Messenger > Preferences > Webcam > Camera Source - set your webcam as default using dropbox. > Camera Settings - adjust settings to suit. > Apply > OK
Take a note of any additional software, if you have multiple choice for Camera Source, you may wish to uninstall any redundant webcam software later to prevent conflicts
> Messenger > Preferences > Webcam - make your selections ( who you will allow to view you) > Apply > OK
When you are both on line and wish to show your webcam > Actions > 'Invite to view my webcam'. This will launch an invitation on your contacts screen when they 'Accept' your webcam broadcast will start- There can be considerable time lag ( 1 minute) before they see you, so dont be too impatient ( You can check the status on the bottom left of your webcam panel. You can 'drag and drop' the frame to a convenient location by grabbing the top border.
There is a shortcut ( webcam icon ) down by your pic as well
Your contacts needs to configure their connection the same as (INTERNET CONNECTION - less webcam reference ) above, or they may get a "webcam not connected" message
If you complete the above and still have problems - check to see if your cam is compatible with Yahoo
To find out what the requirements are for messenger webcams, check out the following.http://help.yahoo.com/l/uk/yahoo/messeng…
I used to get "Server Busy" messages when I was on dial-up, especially at weekends. I guess Yahoo cull all the cams with low bandwidth to preserve server resources when necessary )
You say you have re-installed messenger - I hope you cleaned out the old Messenger folder before downloading - the uninstall software from the Control Panel can leave a lot of software behind to create conflicts.
With Vista, the whole Messenger folder should be deleted on uninstall.
Start > Computer >> Local disk (C) >> Program files >> Yahoo >> Messenger
Thanks For Your Time,