MS Security Essentials has been unable to install updates forsome time on my computer. (even though

since last September or later? before shutting down it has said it was installing 15 updates) (Windows 7 Professional, 64 bit).  

Can not manually Update MS Sec Essentials either, it has an error code. (saying one part of the software is corrupt)

Tried to Uninstall MS Sec Essentials. There is an error code-0X8004FF01 : not allow Uninstall. 

How can I uninstall MS Essentials on my computer to allow a fresh download?

(it won't download as it knows I have the old copy on the computer)

I followed some advice on MS in how to Update, to 'refresh' by clicking on the start button, but then it would not go to

'Getting Started' per instructions, so didn't fix it.

MS rep online cannot help me without signing up for Premium Service.

In Safemode on the b&w dos screen called  Admin/system32/cmd,

the online rep remotely accessed computer,  & it showed

first, access denied, then the next answer back was;

windows could not find the path specified.

Someone will bring over Defender on a USB stick & I'm supposed to keep on pressing F2

while it is booting up, to boot off the stick & run Defender.

Do you all agree this is best thing to do? (other than somehow finding original OS & removing everything,

as someone else said every item on my computer could have the virus imbedded in it.) ?

Thank you very much everyone!  :  )