When you deleted all things Apple there is a specific procedure that assures you did not miss anything. That process is described here: http://support.apple.com/kb/HT1925
Also, if the problem occurs during backup and the winsock reset did not fix it you probably have a corrupt or only partially deleted backup. You may have to delete it manually:
Windows XP backs up the iPhone files to here:
C:\Documents and Settings\user\Application Data\Apple Computer\MobileSync\Backup
Windows Vista and Windows 7 backs up the iPhone files to here:
C:\Users\user\AppData\Roaming\Apple Computer\MobileSync\Backup
In both user is your logged in Windows user name. Delete EVERYTHING in the backup folder.