I installed an old version of GlassFish application server. I have uninstalled it and installed a new version in some other directory. For the old version, although I have uninstalled it, the original installed folder c:\GlassFish is still there. SO I tried to delete this folder. However, it can't be completed deleted. Most of the sub folders under "C:\GlassFish" are deleted, but for 'lib" it can't be deleted. Windows XP pops pop up showing "Access denied --- make sure the disk is not full and the file is not being used." Actually nothing is using it (it has been uninstalled already), I tried to open the "property" of the folder and uncheck the "read-only" check-box, it did not help either.
Most likely glassfish, or some part of it, is registered as a service and is still running.
Have you rebooted and tried deleting it again?
If that does not work, grab Process Monitor from sysinternals and configure it to monitor the lib directory. I should be able to tell you what process is using the directory, and you can then kill that process.
There is also a slight possibility that your anti-virus software has the directory locked. Happens to me occasionally when deleting software.