So basically your windows is broken. Did you have a virus? Any background to this issue, what you tried to fix it? Or did this happen because you tried to fix something else? You also probably mean rundll not rIndll.
Is there a restore point you can try to recover to?
http://support.microsoft.com/kb/306084 Although with an issue with rundll it may not work at all.
You can try to do a Repair setup of XP off your disk, that will restore any files it finds missing or corrupt without touching your existing files
If that fails, you need to backup your files, make a note of your settings and isntalled programs, and re-install Windows fully. You can just install Windows over the current setup, but it may be better to format the disk and start totally clean.