Internet explorer not opening unless 'run as administrator' Vista

I have just received my new Inspiron 531 with Vista (I couldn't persuade Dell
to sell me one with XP).
I have set it up and initially all was well. Now I have installed all my
programs, I find that I cannot open Internet explorer by double left clicking
the desktop icon.
What happens if I do that is either:
C++ runtime error message or
It says not responding and 100% but does not display the page.
The way I have found around this is to right click the desktop icon and left
click 'run as administrator'. This opens up google straight away.
I thought initially this may be because my user profile was not set as
administrator, but I have reset me as administrator now.
Then I read in Personal Computer World that Vista comes with Administrator
level access disabled. I followed their instructions as to how to reset it
but became lost (I think they were using a different version of Vista to
reset user properties).
Then I rang Dell Helpline who said we are now closed! Apparently when users
get home from work and in front of their PC (6pm) they have closed and gone
home and only the expensive technical phone line for business users helpline
works!
They are getting me a call back from someone at home tonight from the free
phone line if I am home by 530pm.
They are going along the lines of assuming that McAfee has restricted access
to internet explorer.
Last night they talked me through resetting some of internet explorer
settings, and had me close down McAfee Security while I made adjustments to
Internet explorer.
This didn't work at all, so I put McAfee back on until a solution arrives.
This is a niggling problem, and hopefully not a serious one. I like the
product and am satisfied with the deal.
I cant believe that Dell have a business helpline open outside business
hours, and home users who must buy a lot of Dell PC's are left without help
in the evening when they use their PC's.
I can't tell Dell customer service I am satisfied (which they seem to be
concerned about, I am beginning to think they are paid for each person that
says the S word). I would be satisfied if the after sales helpline is as good
as the product appears to be.
Does anyone know how to open internet explorer without pretending to be
another administrator?