I just found your post in the Off Topic folder and moved it to the Install/Activate folder.
To find out what action OneCare requires you to take to go green from yellow/fair, open OneCare. The main program screen will have a banner at the top explaining what actions need to be taken.
"worms" and "slow" don't give us much to go by, but if you have other security software remaining on the PC it can cause performance issues as multiple protection programs will conflict.
If you need help, please contact support:
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve