jaugustine wrote:

When I plug a USB flash drive into a USB port on my PC, I have to
wait until every file on the flash drive is checked for media type of
file(s). However, if I remove a HD, with thousands of files, from
another computer, and mount it in a docking station that plugs into a
USB port, this takes much longer (searching for media files).

What you describe is not attributed to AutoRun/AutoPlay but of scanning
for media types of files to build a thumbnail cache file (thumbs.db).
If you don't use thumbnails then you won't incur the slowdown to build
the image cache. If you give files a meaningful name, you don't need
thumbnails to determine what is within each file.

https://en.wikipedia.org/wiki/Windows_thumbnail_cache

If you use thumbnails but keep deleting the thumbs.db file, like setting
the disk cleanup wizard or other cleanup tool to delete the thumbnails
cache, then the file gets rebuilt on each visit to a folder and that
takes time to scan within each file to create an image for each file.
If you configure Windows Explorer to not build a thumbnail cache but
have thumbnail view enabled then thumb.db has to get rebuilt on every
visit to a folder.

In Windows Explorer, go to Tools - Folder Options - View, disable the
"Do not cache thumbnails" to have thumbnails and enable it to prevent
building a thumbnail cache. Changes to these settings are for the
currently selected folder in Windows Explorer. If you want the settings
to be effected across all folders, be sure to click the Apply to all
folders" button before exiting the settings dialog.

Note: In Vista and later, this option got renamed to "Always show
icons, never thumbnails", so the option reversed its setting - disable
to show icons in XP, enable to show icons in Vista+.

How can I TURN OFF "Auto Play"?

http://lmgtfy.com/?q=%22windows+xp%22+disable+autoplay

No mention of which edition (Home, Pro, etc) of Windows XP that you have
(https://en.wikipedia.org/wiki/Windows_XP_editions). To narrow the
search, add the edition to the search criteria.