Can my computer get a virus by opening a pps, doc or wmv email attachment coming from a infected computer?

Yes there is and it's highly possible your computer is already infected. I'd recommend getting anti virus software if you don't already have it and doing a thorough scan of your hard drive. You should never open email attachments from anyone even if you know and trust them. Attachments like jpg files can be infected in transit from the sender to you. Also tell your friend not to click on the run button every time he sees it pops up without being very certain it's harmless. I use the free Avira anti virus that can be used to check individual files from the context menu (right click menu) which has been helpful for me when confronted by suspicious stuff on the Internet.

yes you can

The mastermind can chose to call a binary file picture jpg ect, and when you open the binary file it will mess up your system. - if you don't have any anti virus. depends on alot of things.

You would be advised to use your anti virus software to remove the file, Judging from your friends experience it sounds a nasty piece of work;