Windows 7 issue

I have Windows 7 on my partitioned iMac. I also have an external back up hard drive just for Windows data. Whenever I use Boot Camp to start Windows 7 a pop up screen comes up at the end of the booting process and asks what I want to do with the drive -- it's like it has never seen it before.

It does not do this when I use Parallels.

How do I fix this? Thanks.

I'm not sure you can "fix" it other than not attaching the external hard drive until after Windows 7 boots. I'm assuming here that you have your Boot Camp partition setup to boot separately and are using it also as a virtual machine in Parallels.