You can replace rundll32.exe with a new copy from the Win Me cab set as
follows.  However it is possible that your PC has been infected by a
variant of the CoolWebSearch parasite.

See Variant 24. CWS.Control at
http://www.spywareinfo.com/~merijn/cwschronicles.html and also
http://www.pestpatrol.com/pestinfo/c/cws.asp.

Download and use CWShredder, merijn's removal tool from
http://www.spywareinfo.com/~merijn/files/cwshredder.zip

You may also need to replace control.exe and rundll32.exe with new copies.

Control.exe is contained in WIN_16.CAB and Rundll32.exe in WIN_17.CAB of
the Win Me cab set and can be restored using MSConfig | General | Extract
File ... and following the prompts.  The "cab" files are in the Win9x
folder on the Win Me CD and also in either the C:\Windows\Options\Cabs or
C:\Windows\Options\Install, which depends on the media from which Win Me
was installed.  See MS KB129605 - "HOW TO: Extract Original Compressed
Windows Files" (http://support.microsoft.com?kbid=129605).