The old permissions problem - Can't install Flash

Question

I know this is an old problem but I have tried every remedy in the book and some I never heard of.  I simply cannot get access to the old dll file.
Vista tells me I don't even have permission to view the permissions of this object.  So, to put it simply I can't install Flash 10.1 and the old one has been uninstalled except for the troublesome dll file. 
I have tried every method of either lowering the permission level or raising my authority without success. I have even tried some risky approaches.  Is there a way to force the installer to install the new version to a new location?
TIA.
[I have spent hours on this both yesterday and today.]
Len

Answer 1

Hi, Forgive me for omitting the essential info. I am running Vista Home
Premium (32bit), My primary browser is Opera 10.61.   I also have a
recent version of Chrome and IE 8 on my machine.
The error message on installing Flash 10 is that it doesn't have
sufficient permissions to write to
Windows\system32\Macromed\Flash\NSPWF.dll:5).
Since my previous note,I have temporarily solved the problem by
downloading the xpi version of Flash and putting the appropriate files
in the Opera plugins directory. However that does not solve the problem
for Crhome or IE8.
The larger problem is that I have run the installer as administrator,
logged on as administrator, tried changing the properties and owner of
the dll file and the entire Macromed folder.  I even tried renaming the
folder. Permission is always denied.  The most offending notice is one
that tells me that I don't even have permission to see or edit the
permissions of the dll.
Note: I did check to make sure that no identifiable processes were
running that would not let me access the dll.
Thanks.