XPS 420 compatible with WIN7?

As far as Dell are concerned the XPS-420 is an obsolete machine, so you shouldn't expect any updates on anything from them. My XPS-420 has been running Win 7 64 bit with 3GB of memory for 6 months now with infinitely better reliability and performance than the 32 bit Vista it came with. Upgrade it as fast as you can after checking for drivers for any additional hardware you may have. 

The XPS 420 is compatible with Windows 7 (I have installed it without issue).  If you go to the Dell support page for XPS 420 drivers it does not show Windows 7 since Dell never shipped the XPS 420 with Windows 7 (but that doesn't mean that it's not compatible).

Just make sure you are running the A07 bios before you upgrade, which will be the last bios update for this model. Win 7 runs great on mine. I've run both 32bit and 64bit and both are fine.

Why is the A 07 bios necessary before upgrading the 420 to Windows 7 64 bit???

My hard drive recently died (Vista Ultimate) and have a new hard drive coming in a day or so along with am upgrade version of Win 7 Pro 64 bit. 

Since I'll be installing a new WD 1 TB SATA II drive before clean installing Win 7 Pro, how do I upgrade the bios on a non functioning, non bootable computer prior to adding the Single new hard drive?

Help please!!

Thanks

Short answer you dont.

Other answer would be to make a bootable USB flash drive with dos and download the bios update file.

OR

Make dos bootable cdrom with bios file

OR

install vista on the drive, download bios, install.

then upgrade.

VISTA DRIVERS work  with windows 7 just as win2000 drivers work with XP.