Yes.
Do you mean the games say "compatible with windows 98?" and you have Windows XP? Games are backwards compatible. Meaning, if the games say "windows 98", windows 95 is ok (anything before windows 98 will work). But it is not forward compatible--Windows 2000, windows xp, etc. will not work. does this answer?
Windows works with IBM machines, though Windows '98 is incredibly obsolete at this time.
Many applications and games written for or compatible with Windows 98 will run on Windows Vista.
Yes the claim is that vista is compatible with programs designed for windows 98 and vice versa.
No. Office 98 is a Mac version.
Support for Windows 98 was dropped after the 2.0 line. Firefox 3.0 and higher are not compatible.
Neither one is a particular computer (they are manufacturers, not model names), and neither has a product lineup solely compatible or incompatible with Windows 98. IBM made several workstations with PowerPC processors that obviously cannot run Windows 98, and newer Macs have Intel processors that can run Windows 98, though the hardware is not fully compatible.
All versions of Microsoft Office (with the exception of those created for Macinthoshes) up to and including Office XP are compatible with Windows 98.
Autocad 2000 and earlier.
You can try to run it in the compatibility mode. But 99% of games for Windows 98 will not work under Vista.
Yes, the Saitek X52 Flight Control Joystick is compatible with Windows XP.