Windows 98 Second Edition
Product Key: DMWRC-T9XP4-GJ2P8-26G66-V9WBB
This is an official ISO file from VHD Vault and it can be comfortable for VirtualBox. They are NOT used for VMware, QEMU, Microsoft Virtual PC 2004-2007, Hyper-V VM Connection and Sun xVM VirtualBox.
So click the ISO IMAGE button and download. It takes 2-18 minutes on a high speed KB/s-MB/s, 50 minutes depending on your internet speed or 10-70 hours due to a lowest speed (e.g. 124B/s, 1.9KB/s 2.3KB/s).
So, enjoy your Windows 98 Second Edition!
If you want the Resource Kit CD, go to:
Google > archive.org > ^SOFTWARE^ > CD-ROM Software > Operating System CD-ROMs and find the resource kit CD-ROM (ISO image).