I need to know what pkarchive84cb.dll is because everytime I right click one of my files to delete or to go to properties or ANYTHING it says "Unable to load module: C:\WINDOWS\pkarchive84cb.dll pkarchive84cb.dll" That is not a typo, it does say it twice.
It doesn't really make sense to me because of the problems you are having but the only thing I could find with that file name involved Ad-Aware. http://www.lavasoftsupport.com/lofiversion/index.php/t10897.html If this doesn't help, post back and I will try again.