Will Windows 7 work on my XPS 420 desktop

Yes it will work. Some have reported problems with the mini viewer not functioning correctly

My xps 420 works great with Win7 64 bit. Run the Upgrade Advisor to check your specific hardware and software. A clean install is best with any OS. No problems with the mini viewer either. To do a clean install with the upgrade disk, boot to the win 7 disk, choose Custom Install, then choose Drive Options to format the drive and install win 7.

Thanks so much for this info. It's great to hear a fellow XPS 420 has made the switch with no issues. I've had this running for over a month with little issues till about 2 weeks ago when an upgrade came down from MS & every since it's been running not so great. I haven't had any issues with drivers, but I've had a couple of situations where my programs stop responding & it has gotten so bad that I've had to force shut downs to get things moving again. I did add an additional 4 gb of ram to the system in hopes of making things fly, but it's been a bit of a mess. Thanks again for your time & your help.

Thanks for this info. I've actually has this running on this computer for a couple of months, but when I started having problems with 7 I went to Dell's site where it said that 7 wouldn't work in my XPS 420. Odd, huh? I am having some issues & trying to work through them here. Thanks again for your time & help.

In order to list drivers for an OS on a specific machine, Dell has to go through extensive testing to make sure the drivers work.  They don't do this on machines as new OS's come out ... generally.  So, it is not necessarily that they say it won't work, but that they have not thoroughly tested it and can make no promises.

Thanks for that info. My mini viewer doesn't work, but I really don't care about that as much as everything else working properly. I appreciate your time & help.