Your husband can download as a "save" file rather than a "run" file, and then burn the driver to a CD or copy it to a flash drive... Were it mine, I would download all 6 of the most needed drivers and install them in this order: Chipset, Video Graphics, Audio Analog Devices, Network, and BIOS... then possibly the two Diagnostics files.
Then install them in that order. You will be fine copying them to the new hard drive with Windows Installed, then installing them from there.
If you do not have a Windows XP disk, be sure the computer is registered to you at your current address by updating that registration at the Dell site, then call them to ask that they send you the Windows XP Service Pack 3 disk. Dell may do it free, or they may charge you $12 to $14... and it will arrive in four business days.
Format the drive using the Dell Windows Disk, then install the drivers you have downloaded, using the list above...
You can get to those drivers by using your Service Tag number off the case of your Dell 4700.
Good luck. Come back if you have problems.