The problem is with the specific RAM. It is, in part, latency differential. The SPD (the little black chip in the corner, called the Serial Presence Device) will communicate its settings when popped into the MB. However, this does not guarantee the 2 rams will be good housemates... to test the new 128 MB RAM, put it into Socket 0 (the first, or if in doubt, the slot closest to the CPU), then test the system. If it works, then add the 64MB that was in the slot closest to the CPU to be the housemate of the 128 & test. If it works... then you have to test for quite a while to see if any unexplained BSODs (Blue Screen of Deaths) occur (typically due to RAM error). If all is well, then you have a 192 MB Windows 98 machine.
Windows 98 is a good OS, if you run it properly. It should be Win98SE, English. The best thing is to update it with the "Unofficial Win98SE SP2.1", here, after a fresh install (but you can use SP2.1 even with an old install, as long as it is ENGLISH Win98SE). Its OK to put this sort of question (e.g., hardware advice) in the Tech forum, where it has a good chance of being spotted by both those it can help & those that might be technically inclined to answer.