You are aware I'm sure that Windows 98 is no longer supported by Microsoft, so using it online will render you far more vunerable to virus / malware attack.
The Dell should have come with either a copy of Windows on a restore disk, or on a hidden partition on the hard drive itself.
To access this partiton, you need to enter your BIOS setup screen on bootup. The key you tap varies, but DEL or F2 are common. For more information see the Dell site, but I note they are no longer supplying 98 recovery disks.
A phone call or email may help