BleepingComputer.com: cain and abel

i am interested in pen testing and so i downloaded cain and abel. as i was told it was an all in one sort of program. however every time i've ever run the program it has caused so much damage to my system that i have had to reinstall windows every time. and i can only run the program from safemode (i was using win xp pro corp) from a regular boot i cant run the program. also my antivirus goes ape when it finds it. why is it that cain and abel messes up your computer so much making it a program that's not worth the trouble to use. because of the damage it does to the computer it's run from. maybe i'm paranoid but because i only see the word cain under the program is it thew writer of the program that's abel and he takes control of your computer when you install it, or is it like the fable where abel kills cain ergo your computer? does anyone know of any virus/damage to host free pentesting software that runs under windows without having to buy an airpcap usb stick? and why does cain mess up your compuetr and are my paranoid suppositions true or false. and why wont windows run it from a regular boot. and is the damage the program does intentional or not? thanks and if this is too long winded then let me know if i should edit this post and bullet item the questons? thanks and if you cant help please reply that so i know if im being ignored or not.

Have only played with it in a very limited manner quit some time ago.
Yes, it is a very powerful tool. Not for the novice.
There may be several reasons`s you AV flags it. Considering what it is designed to do. Some of it`s code, actions probably very much mimic known malware behavior. Some of the code may have been borrowed from malware code or the other way around.