Hotmail account hijack

[BrendonF]

Not sure if this is the right place to post this. On 24th February I got an email to my hotmail account (which i use for all of my personal email) from the sysop of an online forum i am a member of saying that i sent them spam and if i did it again i would get banned. I have never sent spam to anyone. They also said that if i hadn't intentionally sent it then it meant my computer had a virus. There were also a lot of bounce back emails in my inbox of someone trying to sell mobile phones. I definetely didn't send these. I did a virus scan (i have eset nod32 installed) and it said my computer was clean. This left me very confused. A week later it happened again and i found myself unable to log into that online forum. I also got another email from someone on my contact list saying that they had received spam from me. I investigated the hotmail website and from the forums it said that my computer must be infected by malware. Once again i did a virus scan and it found nothing. I changed my hotmail password to a strong password and changed my primary question as recommended by my reading of the hotmail forums but still spam was going out from my hotmail account. Dave said i should check my signature settings and holiday settings but but i don't have anything set for these, in other words these are blank. I have also been reading the hotmail forums and there are many people complaining of similar problems to me and saying that hotmail's recommendations of how to fix the problems (ie change password, primary question and check signature settings and vacation settings) do not work. Many people are saying that they believe that hotmail's database of usernames and passwords has been broken into and that accounts have been stolen and used to send spam. These people also say that hotmail is unwilling to admit there is a problem. I am considering closing down my hotmail account and opening a gmail account instead. I have deleted everyone in my contact list as i don't know any other way of stopping all of this spam going out. I have emailed the sysop of the online forum pleading for her to unban me but i have received no reply. any help would be appreciated. I am quite sure that i am not the victim of a phishing scam. I am very careful about that sort of thing.