We have a Lan of about 80 Windows XP Pro and Windows 7 Pro clients which connect to 4 Windows servers; two Windows 2003 R2 Standard and two Windows 2008 R2 Standard. I don't have a domain, we have a Workgroup configuration.
We have files and folders we share with the clients, mostly pdf's, Word, and Excel documents. Our files contain Internal Procedures that our users refer to every day, but we don't want them to be leaked outside of our organization.
How can I prevent users from stealing these files from our company by copying to pendrive, email, etc..?