If you don't want to sell it, then you need to lower your goals, play a different game from the same genre. For example, I am a simracer. I was used to playing AAA racing titles till I got fed up of buying new GPUs every year for them. I resorted to retro gaming and "downgraded" to some of my old favorite racing games, like the MicroProse Grand Prix series (GP1, GP2, GP3...), IndyCar Racing 2, NASCAR RACING, Monster Truck Madness, which were playable in older computers like yours. The same fun I'd have with modern AAA games, but in a very economic way.
IMO it's better to play period-correct games for that machine. With a 1998 computer running Windows 98 SE, I'd want to play Counter Strike (1999), which was based on HL1, or Quake.
For example, you want HL2. Why not play a different first person shooter game from the same era as that 1998 computer, instead of a 2004 game? It's just my 2 cents.
"Design isn't just what it looks like and feels like. Design is how it works."