After Office 2000 sp3 install Excel 2000 unable to open file

While using sp1 Excel 2000, or Excel 97 the *.XLS file opens without
any trouble. However, after installing Office 2000 sp3 - Excel 2000
can't open the *.XLS file and gives the message "Unable to open the file".

Excel 97 still uses the *.XLS files just fine.

How do you either remove Office 2000 SP3, or get around this problem ?

Thanks.
Edz. . . . .

Found a work around

I am using another anti-virus product so. . .

After Office 2000 SP3 Install you may see the
error -> "Unable to open file" When you try
to open an existing Excel *.XLS file.

Open a DOS window and change directory to the
root directory using the -> "CD \" command.

Find file -> officeav.dll using
the -> "Dir officeav.*/s/p" command.

In my case the file is in directory

"C:\_Norton2\IE2005\Norton AntiVirus\"

While in DOS, change to that directory.

CD "C:\_Norton2\IE2005\Norton AntiVirus\"

Use the Regsvr32 command to unregister the DLL.

Regsvr32 /u officeav.dll

Then rename officeav.DLL to officeav.old

Do a reboot of the computer.