I recently installed ClamXAV (an freeware anti-virus programme for Mac) and did a check. Surprise, surprise, I had a Trojan hiding on my iMac, named java.classloader. I then went to the directory and deleted the infected file. Sorry to all Windows users whom I may have infected.
I then did a drive-check, which, by the way sorts your Mac out if it is behaving funny, like ignoring drives, or if you're on blogger find the photo toolbar missing..
Here's how to do it:
Restart your Mac, press and hold Command and s
It will give you a whole lot of stats. When it is done, type in fsck -fy and enter.
It will take a few minutes to sort out your drive and fix all problems.
Once it says that you Mac is fixed, restart and "there you go!"