PM system spam attack

[Rich99]

Hii all. Yet another a spam attack. Although the registration has stopped, and Ive disabled the PM system, somehow im still getiing covered in spa, through the Private Message's. Im getting this:

"Subject: Re:Urgent security update
From: "AV@icosiphci1983.com" <AV@icosiphci1983.com>
Message-ID: <20140103142324.f191dafdfb40@>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
X-Priority: 3
X-Mailer: vBulletin Mail via PHP
Date: Sun, 05 Jan 2014 11:09:06 -0600

Dear User
We hasten to inform you that your PC is at risk of infection with the new generation
Please urgently update system to install the update.

Just download and run the update will be installed automatically.
Thank you for your attention
http://fREMOVED.pp.ua/pc.php"

Like i said, ive closed the PM system, yet somehow the user is still sending them out. Any ideas? Should i just remove the PHP script that runs the PM system? Or should i do a re-install? Just nothing i can do about this right now, very frustrating.