1. I tried to use it years ago and installed it for 1 day. But all it kept doing is popping up messages and bothering me asking me to accept or deny things. Is there a way to stop that?
Why would you want to disable this from happening? This is exactly what the program is supposed to do, which is control what programs can access the Internet and what from the Internet can access your computer. If you start a program and get this popup box, make sure you check the box to Remember my answer
before clicking YES or NO, that way it won't come up again when you run that program.
2. I'd also like to know if Zone Alarm changes any system, or internet settings so if I ever want to uninstall it I'll know that my pc is back to normal and that I don't have to manually go to certain areas of my system or internet settings and set stuff back to the way it was. (ie: such as small stuff or even having to turn my windows firewall back on)
I have uninstalled Zone Alarm on a number of PC's for various reasons, and have never had any connectivity issues after uninstalling it. Yes, you will need to turn Windows Firewal back on if it is turned off, but I would stick with Zone Alarm because Windows Firewall doesn't work very well at all.
3. Lastly before I install Zone Alarm do I have to turn off my windows firewall?
I would, just to make sure that there isn't anything conflicting during the installation. Windows Firewall is not hard to turn off so that isn't that big of a deal.
4. Is this program going to block any of my installed programs (or future installed programs) from connecting to the internet? If so how do I allow them to be connected?
Zone Alarm will pop up a box similar to what you are describing in #1 each time a new program tries to access the Internet. Just do what I said in reply to your #1 question and you will be fine.