These instructions are from Jim Byrd:

Yours is a fairly common complaint, and this is my standard spiel
about such install problems.  There are three things you might want to
check.  In any of these install fixes, to quote Steve Cochran, "It is
essential that no "interfering" software be running during the install and
subsequent reboot.  This is particularly true of antivirus software.  Most
or many of the corrupt installs involve installations while AV or other
software is loaded and these prevent the ability of the setup process to
upgrade dlls, and consequently installations fail or are incomplete."  In
addition, I would suggest disabling ALL Norton software, particularly System
Doctor, if present.

Fix # 1:  Try running ie6setup in Safe Mode.  This was suggested by
Microsoft Support to one correspondent and worked for him after he had tried
the fixes described below.  If it doesn't for you then try the following.

Fix # 2:  First, make sure in Win Explorer/Tools/FolderOptions/View that you
show hidden and system files and show extensions.  If your OS is NT, then
you MUST be logged on as Administrator both to install and for the first
reboot.  Based on my own experience, I believe this is also a good practice
for Win2k, but MS does not say it's required in that case.

Look in your c:\windows\inf folder and see if you find any files named
oemxx.inf which have a length of 0 (zero), where the xx can be any number.
There could be potentially many thousands.  If you do, you need to erase
these.  To do this, first select the c:\windows\inf folder, then hit Search.
In the Search pane on the left, enter oem*.inf and down at the bottom click
Size and At Most and 1 (one).  Then do Search.  When it finishes, you should
have all of the zero length oemxx.inf files listed in the right pane along
with possibly some of size 1K.  Do CNTL A to select all of them.  Now hold
down CNTL while you click on (de-select) all of those at the top that are
1K, so the only the 0K size files are left selected.  Now hold down SHIFT
and click DELETE to delete the zero length oemxx.inf files without sending
them to the Recycle Bin.  It will take some time if you've a lot of these
files, so be patient.  You'll know when it's done.

Now re-start your computer into DOS and run Scandisk C:, fixing any errors.
If you're not NT or Win2k, also run Scanreg /fix.  Re-boot to Windows and
defrag your computer (which will also probably take a little time), and try
your install again from Safe mode..  If it works, fine.

Fix # 3:  If not, or if you didn't have such zero length oemxx.inf type
files to start with, try the following.  Find the c:\program files\internet
explorer\uninstall information  folder (It may be named something slightly
different depending on your operating system, for example, just Uninstall in
WinME.)  It probably will be hidden, and you will have to un-hid it.  Right
click on the folder, select properties, then un-tick the Hidden attribute.
(If you don't have this folder, then create an empty one named:  c:\program
files\internet explorer\uninstall information -  now try your install again
in Safe mode, re-selecting all components, even those already bolded.  See
below.)

Now create a new empty folder and call it something like "IE Delete Backup".
Move the contents of the \uninstall information folder to the new folder you
created.  (Just the contents - leave the old folder there.)   Now try the
install again from the start in Safe mode, re-selecting all components, even
those already bolded, that you want using the Advanced option, and see if
this works.  It has in many, many cases, but not all.  If it doesn't, you
can just restore the files you saved in "IE Delete Backup".  Let us know how
you make out, so that if this doesn't help, perhaps someone else can suggest
something else for you.  Regards, Jim Byrd

Hi,
If you're trying to upgrade from IE5.5 to IE6, see this message from Zee
(Oops) http://snipurl.com/ie55uninstall

Don
[MS MVP- IE/OE]