Malicious code being added to my webpages?

[BBP]

Whoa Akril... I'm sure glad you got rid of that horse! They're a pain in the neck even if you've discovered them instantly.
How did you get that TH?

[Akril]

I honestly have no idea. I suspected that I might have gotten it from visiting one of my own webpages, since my antivirus program warned me that a program was attempting to install myself on my machine, and when I restarted the computer, I had some fake antispyware software installed (which was strangely easy to delete). However, one of the people I was in contact with said that was unlikely. All I know for sure is that I got hit with it at about the same time my webpages started getting altered.