Need help with Software Distribution Service 2.0?

I have been having problems the last few days of several programs not connecting ( CallWave, Yahoo Messenger ) when doing a restart. After doing a System Restore it wouldn't help until I went to a restore point prior to where it showed the Software Distribution Service 2.0 . I have installed Windows OneCare Live and have had numerous problems with it, all have been fixed except the backup program. Every time I do a System Restore it shows that my virus protection is not up to date. The Microsoft Tech. that is working on this problem informes me that that is a know issue with System Restore. Do you know if it is necessary to have the Software Distribution Service installed. I don't remember installing it and figured it was installed via the update for either the OneCare Live or the Windows Update. I have had numerous problems with the Automatic Update and at times have to check manually and get them that way. The last one I did that way downloaded and installed 2 times and neither show up under the Add/Remove Programs.