Migrating Windows 7 to Mac

I have a couple of questions about migrating Windows 7 to my Mac.

1. Will I get a Virtual Machine of Windows 7, or would I just get the files copied onto my hard drive?

2. Approximately how long should the migration take?

3. What are the chances of me getting a virus on my Windows PC?

4. Will all of the files be deleted on my Windows PC after I migrate?

Thanks,
Stephen