Me and most of my friends stayed with Windows 98SE to the (bitter?) end. 😁 I remember trying Windows XP when it first came out, and it was running noticeably slower than Win98SE with a Thunderbird 1.33 GHz and 256 MB RAM. I clearly remember that one of the first games I tested (if not the first) was Return to Castle Wolfenstein, which ran fine on Win98 but on XP... ugh, it ran like crap (d'oh, 256 MB of RAM!).
I had also tried Windows ME and Windows 2000 multiple times in the past, but always ended up having performance/functionality issues that forced me to go back to Windows 98.
I finally made the jump to Windows XP at the end of 2002, when I upgraded to my trusty Thoroughbred Athlon XP 2200+ & 512MB RAM (which I still have in perfect working order on the same Biostar M7VIT Pro motherboard). At the time, Windows XP SP1 was already available, which had made XP finally usable, although I still had some games that refused to work properly on it - like Nocturne 1999, Need For Speed 5 Porsche and others. By that point, I didn't care too much about older games, because I was more interested in the latest and greatest games that ran great on XP (especially after I upgraded to 768 MB RAM).
Anyway, as Joseph_Joestar said, DirectX 7.0 is without question Windows 98 territory. Nowadays, you can run most Direct X 7.0 games on XP just fine, since there are many patches available (in fact, you can run most of those games on Windows 10 too 😁 ), but that's neither here nor there...
2 x PGA132 / 5 x Socket 3 / 9 x Socket 7 / 12 x SS7 / 1 x Socket 8 / 14 x Slot 1 / 5 x Slot A
5 x Socket 370 / 8 x Socket A / 2 x Socket 478 / 2 x Socket 754 / 3 x Socket 939 / 7 x LGA775 / 1 x LGA1155
Current rig: Ryzen 5 3600X
Backup rig: Core i7 7700k