Try these in order , until you get a fix .
Repair IE6
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Upgraded IE & you have problems .
Microsoft provides a patch to rectify the problem:
When you run this executable, when it prompts you whether you wish to overwrite Newer files,
make sure to click YES for each file (do not select "No" or "No to All"

.
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Go back to a good copy of the registry .
Toggle F8 ( when , verifying DMI pool message comes on ) or Press
Ctrl during bootup , depends on your computer .
Select , Safe mode Command prompt
After the C prompt , type , scanreg /restore
Follow the prompts and select a registry dated prior to the problems .
This article describes how to restore a backup copy of the Windows 98
or Windows Millennium Edition (Me) registry
scanreg /restore
Start the System Restore Tool from a Command Prompt in Windows XP (Q304449)
Restore Operation Failed (Q220878)
The information in this article applies to:
Microsoft Windows 98
Microsoft Windows 98 Second Edition