Windows Live Mail sending Spam from hotmail account.

A friend has a laptop running XP SP3 and uses Windows Live Mail to access his Hotmail account.

Recently spam  emails advertising various drugs are being sent to contacts of his apparently from his email account.

This is happening two or tree times a week

He only realised because of returned mail from dead addresses.

Is it likely to be a security problem on his laptop or has someone acked is Hotmail account?

Advice please!
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I would say that he has a virus / malware on his machine.
If you google "botnet" this will explain more.
Sounds like a virus infection.  Download a virus removal utility, Malwarebytes-update the definitions and run a full scan.  You might have to boot the computer into safe mode to delete the virus.  
chrisfixitAuthor Commented:
Hmm apart from Panda Cloud which he has.. I ran Trend Housecall, Malwarebytes, SuperAntiSpyware, Sophos Rootkit Remover.. nothing shows ..
Are you running the scans in safe mode?
I would download spybot s&d download the latest updates for it then reboot into safemode and run the scan.

Another one to try is smitfraudfix.
chrisfixitAuthor Commented:
He got a new Gmail account

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