Temp. IE Files Deleted, Few Moved to Legacy Path

Last week, when I started one of my Windows 2000 Pro O/S's, it took a whole
minute for the Desktop icons to appear.

I checked and everything is OK, but I found that the free space on that
drive C: increased by ~ 1.5 GB!

I feared for the drive health and backed it up. Then I compared that
backup.log with the preceding backup.log, and it turned out that the
Temporary Internet Files, Cookies and History folders were deleted from the
%USERPROFILE%. (I never deleted them before.)

Also, to my surprise, new Temporary Internet Files, Cookies and History
folders were created and slightly populated under %SystemRoot% directory!
These are legacy paths that belong to windows 9X and NT era, not to Windows
2000.

I searched the Windows 2000 Registry and found that these legacy paths do
appear in these Keys:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet
Settings\Cache\Special Paths\Cookies

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Url History

So, I ask:

Is it a normal behavior for Windows 2000 to "vomit" a huge amount of Temp.
IE Files and Cookies when its belly is too full, without user's intervention?

What is the purpose of the legacy paths %SystemRoot%\Cookies and
%SystemRoot%\History in the Windows 2000 Registry keys?

Are the newly created Temporary Internet Files, Cookies and History folders
under %SystemRoot% related in any way to the a/m Registry keys in Windows
2000? Otherwise, why were they created?

Please advise.