Do you have SBC Yahoo as your internet provide?  If so, call their technical support - it seems to be a common problem with their software.

Steve

Yes, the problem seems to be with SBC Yahoo only.

You may also restore the mshtml.dll file using the SFC utility. Follow the steps:

1. Click Start and Run.

2. In the Run dialogue box, type SFC /SCANNOW and press Enter

3. Follow the onscreen instructions.

Also, register the following files:

In the Run dialogue box, type regsvr32 urlmon.dll and press Enter

Thanks!  I sent a note to a tech for Yahoo, we will see if we get a response.  I aslo tried your line #2 and my system did not recognize it. 

using SFC /SCANNOW wil help in restoring the corrupted system files and is a very useful utility. Ensure that you have typed the exact string. Visit the URL for info:

http://service1.symantec.com/support/tsgeninfo.nsf/docid/2001011114021106