Can I run Windows Update before installing an anti-virus program?

Always state your Internet Explorer version (e.g., IE8; IE9) as well as your full Windows version (e.g., Win7 32-bit; Win7 32-bit SP1; Win7 64-bit; Win7 64-bit SP1) when posting in a forum. Please do so in your next reply. THX

How long was your brand-new computer connected to the internet before you attempted to install Microsoft Security Essentials (MSE)?

Was MSE offered by Windows Update or did you intentionally choose to (attempt to) install it?

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Related references may include:

Check list for installing Microsoft Security Essentials

http://experts.windows.com/w/experts_wiki/89.aspx

Can I install Microsoft Security Essentials [or any other anti-virus/anti-spyware application] to clean up my already-infected computer?

http://answers.microsoft.com/thread/87058857-d181-4019-a723-efd9a49d9275

Hi Pa Bear, thanks for your response and for providing help with Community protocol:

I am currently using IE8 with Win7,64-bit SP1 (Professional, if that matters).

When I first connected to the internet, IE directed me to www.dell.com, then I used Bing to the Windows MSE site (so I chose MSE) where I immediately attempted to download--probably within 30 seconds of first connecting.  The download went smoothly--it wasn't until the system started to install MSE that I got the "File Corrupted" message.  I tried twice with the same result.   Hope this helps--thanks again! 

I'm reviewing your "Related references" now. 

When I first connected to the internet, IE directed me to www.dell.com...

Did a Norton free-trial or a McAfee free-trial [PICK ONE] come preinstalled on the Dell computer when you bought it? (Doesn't matter if you never used or Activated it.)

Comment: Most new Dells come with either Norton or a McAfee free-trial (or prepaid subscription) preinstalled. See Check list for installing Microsoft Security Essentials.

I reviewed the "Related references" and they confirm what I was thinking--that Ido need to do all of the updates before downloading MSE...

ONLY if another anti-virus application is already-installed & its Definitions are up-to-date!

A computer should NEVER be connected to the internet for extended periods (i.e., long enough to run a manual check for updates or for Automatic Updates to download/install needed updates) without a valid, fully-updated anti-virus application installed.