|You had me thinking I was wrong there for a second, so called five computer shops to clarify your question and my answer.|
Affects On Internet Connectivity:
1) An AV program is made to have no affect on internet connectivity.( We wouldn't buy ones that did?)
2) AV programs like Norton and Nod32, Mcafee will chew up pc resources CPU and RAM, which slows things down. (Not connectivity.)
3) If you are running more than one AV program, it may cause connectivity issues. Because of conflicts between the two AV programs.(Thats why you should only have one installed)
4) If you have limewire P2P programs etc running, you may have conflicts with your AV program, which may cause connectivity issues.(Thats why they are removed for malware removals)
5) If your pc already has hidden malware running, which is designed to cause connectivity problems, through to no connection at all.
6) Even web scanners and email scanners should only hog resources, not change the connectivity.
7) Heavy computer use in your area will affect connectivity, not your AV program.
This was the same run down of answers from all five computer shops? So we must all be wrong then? I wish I was getting paid $100 plus p/hr to give the wrong advice :-)