I am running Vista Home Premium SP2 with Microsoft Security Essentials as my anti virus/malware protection.
When the system is cold booted, instead of the MSE icon appearing in the notification area, another icon appears with the message that 'Windows has blocked some startup programs". On clicking this icon there is a drop-down list with an option to "Run blocked program" and hovering on this shows that the only blocked program is Microsoft Security Client User Interface. Clicking on this immediately displays the MSE icon in the notification area. Similarly, if I turn off User Account Control, the MSE icon appears immediately on initial boot-up. On checking 'msconfig' and 'services.msc' everything appears to be set correctly.
Although this is a stable and constant condition, Microsoft MSE Tech Support have been unable to offer a solution. Any advice will be most welcome.