Problem playing .avi files

When I try to open certain .avi files on my computer, things start to crash. For example, if I just open the containing folder, a message will pop up saying "Data Execution Prevention" and say that Windows Explorer needs to close. If I open up the folder and then quickly open up a file, first Media Player Classic will close and then Explorer will close. This seems to mostly be a problem concering videos involving the Xvid codec. I have just recently downloaded the latest xvid codec and turned of Data Execution prevention for Windows Explorer and Media Player Classic. Same problem except now it just says "There was an error and Windows Explorer needs to close".

Can any of you help me with this? I'd be very grateful.