Hi kubajz
No chance to have Windows 98 run natively on your new Hp Vista laptop (the hardware is simply not supported at all). But Windows 98 might run just fine in emulation.
You mentioned you tried to "downgrade" -- I'll assume, then, that you've erased your earlier Vista installation. If so:
1) Either restore a Disk-Image backup of your hard drive from when Vista was installed (such images can be made with programs such as Norton Ghost, Acronis True Image, and Vista's own built-in Backup [but only for the Ultimate, Business, & Enterprise 'editions' -- it's called "Complete PC Backup"]) . . . or run the Hp-supplied "Recovery Disk" (some Hp models require you to create your own ... if this is the case with yours, and you neglected to make a Recovery set, you can order Recovery Disks directly from Hp for a small fee [around $20]).
2) Download and install Microsoft's Virtual PC 2007 ---
http://www.microsoft.com/downloads/d...displaylang=en
3) Install Windows 98 as a virtual operating system within Virtual PC 2007.
4) Install your Windows-98 program in your virtual Windows 98 environment in Virtual PC 2007.
Best of luck
. . . Gary