Well you can often tell your antivirus software to ignore sites that are trusted, same goes with your firewall which is often the same thing these days. Also running anti spyware software which will eliminate things which analyse your browsing, benign or not they can slow you down. Of course running frequent malware removal programs can deal with this, chances are you already have them.
That’s not a bad thing, the most popular browser is the browser that is targeted with the most malware. As someone else said use a less popular browser. IE9 is not bigger faster and better, all browsers are as fast as each other connection wise, even Microsoft cannot magically make the web faster.
Some forums overcome the duplicate post problem with the message “There has been a post since you lastposted. Perhaps you’d like to review that post before posting again.” (paraphrase of message).
Looks like there is a setting on phpBB called Flood Interval which prevents a user from posting too rapidly. Hard to tell but it seems to be set at 15 seconds or less. Admin might try raising it to 30 seconds (or more) to see if it does anything for Ierrellus.