We Could not complete your request, an unknown error occurred(2001).

Please help! I have had this problem multiple times and itunes support has always been able to help correct the problem, but now that my ipod is out of the one year warrenty period, they suddenly don't know what to do and blame it on windows vista and norton antivirus programs(SHOCKING!)I can get to the I tunes store and browse music, but when I attempt to purchase a song, it takes me to the terms of aggreement page and once I agree, it takes me to another error page. I also cannot view my account and get the 2001 error message when I try to authorize my computer. I have checked and double checked all of my firewall setings, internet settings, security settings, etc.. I even completely removed all noroton security programs from my computer. WHen I run a diagnostics test it states that I am connected to the internet and the store as well and that all is well, but alas, I still cannot download songs. I am no computer genuis and therefore would appriciate any advice! I have not been able to get any new tunes for almost a week now and am very unhappy with this situation!!! HELP!!!!