This should be in the PC section, anyhow rundll32.exe can be several things, something you installed or a virus. the way i have dealt with this in the past is to complete a system restore which takes your computer back to a time before the file was installed.
To manually create a restore point:
Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. You need to set a date in the past!!! bearing in mind when you may have picked up the rundll32.exe file
you can follow this link to give further info
http://www.microsoft.com/windowsxp/using/helpandsupport/getstarted/ballew_03may19.mspx
marko, October 2007