I am not sure about Dell, however Gateway has the same sort of "compatability check" that it does to make sure that it is a Gateway PC. I have a friend that I walked through this process and he was able to do it.
You need a Windows 98 boot disk or a bootdisk from www.bootdisk.com
Boot with this disk and create a partition using the fdisk program located on the disk. After you create the partition, use the "format c: /s" command to format the disk and make it bootable. After this boot with the disk and choose "Windows 98 with CD-ROM support" (or something like that....key here is CD-ROM support.
After it loads, goto that drive ie, D: or E: (whichever is the CD-ROM drive). You'll know that it's the cd-rom drive because it will have a i386 directory when you type the dir command. Then you want to run an executable on the disk. So let's say that the CD-ROm drive is E:. After booting to the A: drive type:
cd i386 (enter)
When the setup starts, then it will ask you where the install files are located. It will default to "E:\i386". Change the path to just "E:\" and then it should run.
I've done this several times before with other vendor disks.