This article was first appeared on my Blogspot blog in this link https://banadurga.blogspot.com/2007/12/removing-unwanted-Dlls.html Unnecessary DLL files and will simply be cluttering up the system. If you could get rid of these surplus files you would liberate a worthwhile amount of disk space.
• The more files there are in a given directory, the longer it takes Windows to locate and open a file in that directory.
• So, if you can remove unnecessarily, your users might notice a worthwhile improvement in performance. This is especially true of the vital Windows System directory, which is where many redundant DLLs hang out.
• The commonest cause of DLLclutter is file duplication. This happens when multiple applications install copies of the same DLL in different directories.
• When installation an application, it will usually
place its DLLs either in its own directory or in the Windows System directory.
• if the DLL is a shared library the System directory is a better place for
it. If the file is not available in the application’s own directory, Windows will eventually look for it in the System directory, so all applications that require the DLL can be sure of finding it there.
• DLL-related problem is that of orphaned files: DLLs that get left behind after their parent applications have been uninstalled. This especially affects DLLs in the System directory.
• The uninstall utility will assume that these files are shared, but it will have no way of knowing which other applications use them or whether these applications are actually present on your system.
• Inmost cases the uninstaller will play safe and decline to erase any DLLs at all from the System directory, which thus becomes a warehouse of orphaned files.
Identifying DLLs

One way to find this out is to look at the DLL’s property sheet. To locate the DLL file in Windows Explorer or a folder window;
• right-click on it, select Properties, then select the Version tab. With luck, the resulting window will display a short description of the DLL, its version number and a copyright notice, and perhaps also the vendor’s name, product name and several other useful items of information.
• Unfortunately, these details are not always present. not all software developer provides this information.
• In the case of Microsoft applications, searching the Knowledge Base for the DLL filename often yields useful results.
• If the computer is running Windows 98, the System File Information utility is a good source of DLL data. This applet displays descriptions of all the Windows 98 system files, including its 850-oddDLLs – although it unfortunately does not show version information.
• A much more comprehensive source of information is the Microsoft DLL Help Database.
• It will tell you exactly which versions of which applications require each version of the DLL, and also the relative path to the directory where they expect to install it from.

Purging Orphans

• If you want to quickly locate and delete all the orphaned DLLs in the System folder, you will need a utility that does the job automatically.
• The two utility packs which are most popular with support staff are Norton Utilities and McAfee Utilities.
• The best tool for tracking down and eliminating orphaned DLLs is a free utility calledClnSys, by Kevin Solway ClnSys is used by thousands of large companies, and it is completely safe, provided that it is used properly.
• ClnSys works by examining every executable program installed on the computer.
• It works out which DLLs those programs call, then compares these to the DLLs in the Systemdirectory.AnyDLLs forwhich there is no calling programare flagged as orphans. ClnSys then moves these to a backup directory.
• For real belt-and-braces safety, you could copy them to a floppy before deleting them from the hard disk.

Eliminating Duplicates

• Norton Cleansweep and McAfee Uninstaller both include tools which will locate multiple copies of DLLs, and both programs will help you decide how to deal with them.

Norton Cleansweep
• In Norton Cleansweep, the job is handled by the Redundant DLL Finder.
• It is to review the duplicates and to select the files that you think it is safe to erase.
• It can rely on the colour-coding to determine which of the duplicates that should get rid of.
• It is always safe to erase these – in fact, Cleansweep pre-selects these for deletion.
• If a file appears to be the same as one which is in the System directory but it has a higher version number, you should move it to the System directory and overwrite the one already there.
• If the file has a lower version number than the one in the System directory, it is usually safe to select it for deletion.
• If there are two or more copies of the file, but none is in the System directory, move the newest one to the System directory and
select the others for deletion.

McAfee Uninstaller

• The most noticeable difference between the products is that the Norton tool scans the entire drive each time you launch it.
• McAfee maintains a permanent database of DLLs and similar files, and only needs to update it with recent changes, which is a lot quicker.

Conclusion
removing DLLs on a regular basis – perhaps once a month – will produce further savings.

Further Reading: Developer gnome