How do I clear my history of searches in search engines, so others
won't press a letter and see my past searches?

Hello mcmillj-ga

Thank-you for your question.

Removing the history of your searches is thankfully a fairly simple
procedure, some people find the search history a useful feature and
others detest it.

A quick summary of the procedure is: go to the search engine of your
choice and click once in the box you would normally type your search
term.  After a few moments a list will pop up with all your past
searches, use the cursor keys to move up and down the list.  When you
highlight a term you no longer require simply tap the delete key and
it will be removed.  This removes the terms one-by-one allowing you to
keep ones you may wish to.

For further details and how to remove them all in one go:
http://searchenginewatch.com/sereport/article.php/2165181

The full procedure is dependent on which browser you are using and on
what operating system.  If the above link still leaves you unsure,
please ask for clarification and provide me with the details so that I
can help you further.

Thanks, I should have been able to fig that out on my own.

One of the easiest ways to clear all kinds of tracking left in your
Windows registry is to use Microsoft's (Giant) Anti-Spyware currently
in Beta.
http://www.microsoft.com/athome/security/spyware/software/default.mspx

Once installed, open it from the icon on your taskbar, go to Tools
Menu, Advanced Tools, Tracks Eraser.  Check any of dozens of registry
entries that track your PC activity, check to save the results as the
default configuration then execute the purge of all this information
from IE and the registry.  This feature should still work even after
the beta is over and is more inclusive than any shareware registry
cleaner I've seen.  If you could find the saved settings and if they
are stored as an INF, you could simply preserve that file and
right-click to run it against the registry.