antivirus problem, my antivirus won't download!

ive got a reallllly big problem with my antivirus software. first i got panda platium which works fine for 3 days, but after those days it won't update! it says encountered a internal error?????? then i tryed mcafee virusscan 8, i tryed to update that too and it says not connected to the internet, when i was connected to the internet. can any1 tell me what the problem is? should i format my comp?

Some anti-virus programs change your direct internet connection to a proxy connection. Check to see if this is what happened on your machine. Right click on the Internet explorer icon, then click on the Connection tab, then click on the lan server button and at the bottom the advanced button. (You don't have to do any of this if you are using dialup.) If there is a proxy setting, don't change anything, just uncheck the box calling for its use, then try your software update for your anti-virus software. Change it back before you use your browser. This is one possible problem.