XP Loosing Pointers

I've been having a problem with Windows XP that someone might be able to help me with. Short story - only and example of a more pervasive issue:I have a folder where I place downloaded files (zip). Within this folder are 12 subfolders where I move 12 of the zip files in order to unzip the files without mixing differing files.As I unzip the files within each of the numbered folder, I extract files, re-label some, and delete others. Often I combine files into an FS9 flight sim texture folder (for example). Then I copy the zip file label, delete the zip file and the avsim file, and put the zip file label into an empty folder so that I know the file's source.I can unzip a number (the number of files unzipped before the problem occurs varies) of the zipped files, manipulate the files and folders when suddenly I'm unable to delete some of the unnecessary folders/files. The OS tells me that one or more of these folders/files are in use and cannot be deleted (moved to the trash bin). Each time I check to see if there is a connected process but I find no such connection. I can move on to the next numbered folder and complete operations on the zip file and delete all contents without problems. Eventually, the problem occurs again.The only way I can delete these straned folders/files is to reboot the OS.Has anyone seen this with XP? Help would be much appreciated.fb