Open Minded.
Linux is the Operating System behind some of the biggest sites on the internet (Google for instance)
it's regularly chosen over windows for it's reliability, security and of course - price.
Open Source software dramatically reduces the cost and complexity of licensing Commercial software and there are viable, stable, alternatives for most of your day to day computing needs; Applications such as OpenOffice.org can easily replace Microsoft Office for most general purpose tasks and expensive Windows fileservers can be replaced with Samba, seamlessly.
Proprietary databases like Microsoft's Access can easily be migrated to servers like PostgreSQL and MySQL with no loss of data. Using these Open Source databases also makes it far easier to migrate your proprietary Windows database applications to web-based applications in the future or to integrate with an online presence (for instance a shopping cart)
In order to provide the best possible support I work in conjunction with Edinburgh-based Eduqate. Get in touch with Eduqate to discuss how Linux, and we, can help your business.