Well a couple of things to be aware of.
1) NX4 came out before Win7, so you may need to run in XP mode.
2) You cannot run NX on the home edition of Win7.
"Wildfires are dangerous, hard to control, and economically catastrophic."
While what I do can't be considered 'production', I'm running NX 4.0 on Windows 7 Enterprise with no problems that I've ever noticed (in fact, I'm runnig all UG/NX versions back to UG V16.0 without any apparent problems, but of course, this does NOT mean that we officially support this nor that we even think it's a good idea).
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA