There goes another two bit US IT company - down the monopoly drain, e-mail and tell them that due to Microsoft DRM you won't be using Intel processors in any systems you support. This is just as bad as DVD Regional Codes, only designed to benefit the distribution of DVDs by the movie makers.
Use an AMD chip, and start specifying that your data is to be stored in an open format at work, contact your MP and ask for all data the government holds on you to be removed from Microsoft based systems due to security concerns, if you are in business change as much as you can to Linux - if the governemnet wants some data report by hand until they produce the software that works on Linux. Start talking to your customers everytime there is a serious virus/spam/spyware outbreak and when asked state that you don't have these worries because you use Linux on your systems.
One of the best ways I have found when going onsite to customers premises is to automatically scan the problem system for viruses with LinuxDefender Live! from Bit Defender. With the advances in Samba it is much more cost effective to replace Windows based Domain Controllers with Linux systems, or even Apple Mac OS X 10.4 xServes which uses Samba as well, and then implement virus scanning on the servers using ClamAV or another virus scanner. Unlike Microsoft Windows 2000/2003 Server you don't have to worry about CALs when connecting to Samba servers.
Start looking at OpenOffice.org and asking why everyone needs full versions of Microsoft Office on their PC. Use Microsoft Exchange Server? - then Evolution and kMail from SUSE have the Exchange Connector built in and the Connector is now Open Source. You can add it to any distribution, although I recommend and use SuSE