It's funny. Looking up System Commander on Wikipedia I saw VCOM, who also made Copy Commander and Partition Commander, which coincidentally(?) my dad, after cleaning up some of his old stuff, gave me a relatively good copy of Copy Commander ver.9 with the original box (which on it says "Partition Commander Special Edition" was "included", but if it is on the same disc as CC or if it came on a separate disc which is now not in the box I cannot say).
Generally, install 98SE first then partition + install XP. Or install XP on a separate drive.
If you mean to do a "vanilla" (as I will call it) dual-boot system, yeah, but I am trying to attain that "each OS has their own C drive", which is why I am posting again to this topic. I finally did a little test of what schmatzler laid out (using Free FDISK that ships with FreeDOS), and man it is magical compared to the original FDISK provided by Microsoft. It correctly detects the size of the HDD I am using, and skips the annoyingly slow "checking drive integrity" bullcrap that takes forever. And, the reason I tried it to make sure it did do what schmatzler said it did, it does support multiple primary partitions! I was able to create a 80GB primary partition for Win98 "in the front" as the first partition, and then the rest of the space (150GB) for a second primary partition for XP! Finally, to make sure it was all about that "active" status, I set the second primary partition as active, and the XP setup disk manager said that second primary partition would be the C drive! So now I am installing Win98 for hopefully the last time on this time-waster of a machine, and then will install XP, choose a boot manager, and then enjoy!
Oh, and of course create a new topic dedicated to it. 😀
Shout out to schmatzler! Thanks for this ridiculously simple solution!