You could get a free (three hour) demo version of Little Snitch that should be able to show
what is getting anything from your computer; however a real keylogger may have other
tricks or hours of the day, yet should've left a trail in the computer's outgoing net logs.
http://www.obdev.at/products/littlesnitch/download.html
I've not tried the Little Snitch product, years ago the early version was a shareware and
I downloaded it; but had no issues related to remote access or data gathered/sent out.
Some of the independent Apple authorized resellers and service providers in Montana
could help you; instead of paying a Belkin? tech who may not even know Mavericks 10.9
for an unknown quality of support, you could likely get about an hour of Apple trained Tech.
The company simplymac seems to have several locations and a web site near Bozeman
and Helena; comes up when I look for anything near the latter name. Other areas probably
have nearby authorized service providers and a few Specialists.
To discover the cause of an alleged 'keylogger' event, and know how to deal with symptoms
and find their true causes if not a real key logger, is an important aspect of learning and also
to save money for real events that may occur that could involve a need for pro tech help.
Or for hardware issues, that can take on an other-worldly dimension such as twilight zone.
There are areas covered in TheSafeMac to check regarding access issues where someone
could, say, discover your Apple ID, or use another password-protected item you have to go
and do things in your name online; or try to gain access to the computer from elsewhere.
These are not necessarily a keystroke logger; that implies personal access to a computer
to be able to install such an application. Your admin password and sitting at your Mac.
Hopefully you can find the issue, and that it may not be keystroke logging after all.
Oh, I did email thomas_r. at 'the safe mac' about this ASC thread, with link to it.
Good luck & happy computing! 🙂