Have you verified that the file "C:\WINDOWS\system32\rundll32.exe" is
actually missing?
To do this,
1. on the taskbar, click the Start button, then click Run
2. in the Run window, type
cmd
and press enter to open the command prompt window.
3. in the command prompt window, type
dir C:\WINDOWS\system32\rundll32.exe
and press enter. Do you see a "File Not Found" message? If so, read on.
If not, let us know.
4. type
exit
and press enter to close the command prompt window.
Have you scanned your system for virusses, trojans, worms and other malware?
To do this,
a. you must have an updated AntiVirus application installed. Ask if you
want us to suggest a few,
or
b. use a free online virus scanner, like Trend Micro's HouseCall
http://housecall.trendmicro.com/
You may have to perform a System Restore.
To do this,
1. on the tasbar, click the Start button, then click Run
2. in the Run window, type
%SystemRoot%\system32\restore\rstrui.exe
and press enter to open System Restore.
3. follow the instructions on the screen.
Let us know if you need specific help with one of the above, or if none of
the above helped.