I know this is a Windows 7 Forum but a lot of people have XP / W2K3 server type VM's as well.
Two probls CAN arise if you want to install Office 2010 on these systems (BOTH VIRTUAL AND REAL).
(XP or W2K3)
1) MSXML needs to be installed or the Office product won't install
Download here Download details: MSXML 6.0 Service Pack 2 (KB973686)
2) to use some features of Office 2010 you'll have to install at least .NET 2.0 (preferably 3.5)
Net 2.0 Download details: .NET Framework 2.0 Service Pack 2
Net 3.5 Download details: .NET Framework 3.5 Service pack 1
Note as posted you only need these downloads for XP and W2K3 -- NOT WINDOWS 7.