Please do the following...
Open Notepad (Start > All Programs > Accessories > Notepad)
Copy/paste all the contents of the quote box below to Notepad (do not copy the word 'Quote').
Save it on the Desktop as: fixlist.txt
Unlock: c:\Program Files\Microsoft Security Client
Unlock: c:\Program Files (x86)\Microsoft Security Client
WARNING: This script is written specifically for this case, for use on this particular computer.
Running the script on another computer may cause damage to the Operating System!!
again, but this time press the Fix
button just once, and wait.
Please post the new Fixlog.txt
in your reply.
Next, try uninstalling Microsoft Security Essentials from Control Panel/Uninstall Programs.
If you get any error message, please be specific as to what they say, or, capture an image of them using the Snipping Tool.
If the uninstall does not work, try the following: Microsoft Security Essentials Removal Tool Download
Please post back on how it goes.