This is almost a repeat of a post in a similar thread:
As for the napster issue. People have sent me lists of files it happened to but I can't seem to replicate the problem. I've been getting "some" fake results but that's all. I suspect if there is something related to napster then it's either due to adware or ... there is something within these files that is catching onto a weakness of Explorer.
I've been trying to replicate the problem on my mac, so I'll need to try it out on windows to see what happens there. That could take a while since my windows works very slowly.

Is the window that pops up always Internet Explorer? The more details of what happens the better.