Setup usually does more than just copying files, it runs scripts and processes that "tie" the operating system to your individual hardware.
There is a stage in most Operating systems where you can actually make a copy.
In Windows 3.1 - Windows XP this was the dos portion of setup before it went to the Windows shell.
In Windows Vista and Windows 7, the first part of setup simply extracted a lot of files from a
.WIM system image. (After it rebooted, it actually did the configuration.
So, if you were to image the system after any of the stages above, before the hardware gets configured, you should be able to continue - However, versions prior to Windows Vista and Windows 7 will require the media for the Windows part of setup.
You would also need to manually format/partition the drive and copy over the bootloader, but if you had a proper image of the hard drive, it should take care of that for you.
Also, if you were to get any edition of Windows and do a
Sysprep /genralize, (link here), you should actually be able to copy the installation to any hardware - again, you will need to partition / load the MBR first.
edit - I should of just re-read the question! I gave a bigger overall solution/look at this.
For what you want, yes, it is very easy and I used to do it all the time (had a spare machine with LapLink, and I used to transfer files via LPT/parallel cable).
I used to:
- Use a boot floppy to start the machine.
- Format the hard drive, no system files or anything.
- Create a folder called "winstall" (
mkdir winstall )
- Copy the root of the cd to that folder - (I can't honestly remember as it was over 10 years since I last did this, but I think there was just one folder, I386)
- Run setup.exe from the Winstall folder.
This process will install Windows fine and will setup the hard drive correctly, system files and all (Remember that Windows 98 was its own operating system).
Hope this helps.