When I went to login-in to a website (it has a pop up window that asks
for username and password) the window dropped down with my email
adress (it starts with the same letter as my email addy) as well as
another email adress I did not recognize.  NO ONE else uses my
computer.  Is someone hacking into my computer? What should I do
(besides running ad-aware and McAffee)?

If you haven't got a firewall I would install one. They usually log
attempted hacks and give the IP address of who is doing it. A good
WHOIS can then tell you who the IP address is - sometimes it is a
'safe' one such as your ISP perhaps pinging you to see whether your
always-on connection is still active. If its a name you do not
recognise, then it could well be a genuine hack

wolvies

Also I would Get a spyware checker... mainly spy bot search and
destroy and run that(similar to a virus scan). It will get rid of the
spyware that maybe on your system.  Also get a copy of hijackthis.  It
will rid some of the extra start pages, ect.  That are put on your
Internet Explorer!
Hope this helps

http://www.safer-networking.org/en/download/index.html

Download "spybot" from this link.  Install it...follow the directions.
 It will search for any problems/instrusions/hacked stuff..and then
will fix it as well.  Easy!

all comments are good but one problem... it wouldn't physically show
up on the drop down unless someone had tried to manually enter it on
that physical computer... this is because of cache, cookies, etc...

just get a program called tracks eraser or tracks eraser pro and it
will clear all info if you want it gone, but no spyware would do
that..

hope this helps
-kkrazyykkidd