This is from file name NDP40-KB2539636 identified as a .NET 4.0 security update (KB2539636). From this, you can find the bulletin number and look it up for further ID (MS11-069)
The name of the directory is a guid assigned for the install and is where the update has been uncompressed for install.
On Windows XP, the update would create a log file with the KB2539636 identifier in your C:/Windows folder.
Any time you see these KB numbers, it's fairly easy to look up the patch and bulletin info.
As to why it's on this drive, if you look in your System Restore settings, you probably will find that System Restore is also using this drive for its backups. Any drives thus identified with free space are fair game for Windows to create a temporary direcory for use in uncompressing system updates before their application to the OS.
As a cross reference, in Windows 7 Control Panel\All Control Panel Items\Windows Update\View, update history will show an entry referencing KB2539636, its imporance, install status and day installed.