ray_g, worry but don't worry too much 🙂
JLW is right, the realy dangerous commands are not allowed in the forum software.
The clickable e-mail attachment relies on two things, a falsified filename extension and a falsified tag to trick you and your mail reader into beleiving it is something else.
This works because modern Windows Versions don't show the extension of known file types by default but execute them.
An example, when you rename a virus from malware.exe to nice-tits.jpg.exe the attachment is shown as nice-tits.jpg by most Windows installations and if you double click it Windows reads the hidden .exe extension and does not call the program used to view pictures but executes the program.
You can hack a website and install malware on it, even MSN japan was hacked recently, but you can be reasonably save when you have the newest patches for Windows XP, it can become critical with Windows 2000 as support has been discontinued since july 1st.
A file uploaded to the forum or the gallery won't do the trick.
Just don't add websites outside your controll to the trusted zones.
I once had a "signature virus":
I'm a signature virus, please pass this message to all your friends and reformat your harddisks after that.