how can i recover my contacts to notify them that my account was hacked?

[Candace R]

You need to contact the abuse people at Yahoo immediately.

That doesn't resolve the issue of your computer. Your computer probably has something running on it that you don't know about. You will probably need to reinstall Windows, so you will need your Windows serial number. Include all the zeros and dashes.

Find it by clicking on the Windows symbol, click on Control Panel, click on System and Security, click on System, and at the bottom of that window you will find your Windows serial number.