The CD that the OP had/has could have accidently had backtrack put on it when the OP was making the CD.
Clearer?
Yes. But there is an equal chance the CD that the OP had/has could have accidentally had lude Polar Bear images put on it when they were making the disc.
First: How do you "Accidentally" Put backtrack on a CD? One would assume this means that at some point backtrack would have to be downloaded (or perhaps it was downloaded accidentally too?)
Second: even if backtrack "accidentally" put itself on the disc, the only way to "accidentally" install it would be if you booted up the disk and absent-mindedly went through the 10 minute (or maybe longer) install process, which involves changing partitions and the boot loader. All of which have pretty clear prompts and are rather clear that one should tread carefully.
Third: a "penetration testing environment" is not exactly something that "infects" an ISO. especially when said "infection" is nearly a full CD in and of itself.
Basically, saying "I accidentally installed backtrack" is the same as saying "OMG I accidentally installed FreeBSD"- you can't install them "accidentally".
Tell you what patio, Ignore my posts. I'm just trying to help and you keep pushing me further and further into the darkness.
It doesn't help to propose logic-bending theories about software you are apparently not familiar with.