Its possible that something you downloaded/opened put a backdoor or trojan that is causing you to spam. First thing i would do is run a couple good virus scans, including one of the good free online ones that tend to be better at catching IRC related trojans, like housecall at
www.trendmicro.comI'd also double check your remotes to see if anything has been altered. You said it looked like you posted it, can you recall exactly what it looked like? (keep in mind its likely some trojan caused it)
