What you are doing is a bit like getting a Morris Minor to tow a 4-ton trailer. You have a number of problems, but first, a bit of background.....
As hardware speeds and capabilities have increased, so the software writers have been able to incorporate more bells and whistles into their code. Indeed, Microsoft are frequently accused of lazy programming, in that their applications have become positively monolithic over the years. The system you describe ran perfectly well in the early 90s with Windows 3.1 and the very earliest version of MS Office (5? can't remember). You'll probably find the motherboard bus is running at only 25Mhz, the processor at 100 MHz and the video card is going to be struggling as well.
The systems that Win 98 was designed to run on are P450 upwards, minimum of 64Mb RAM, and motherboard bus speeds of 66 - 100 MHz minimum. Both Win 98 and Office 97 make great demands on system resources (RAM, data transfer, video, processor, etc) which your system is woefully short of.
In short, although MS say that you can run Win 98 and Office 97 Pro on a DX4, it's like running through molasses. They say the same thing about Windows NT (386SX with 12 Mb RAM, so they say - you just can't do anything with it).
So, my advice is to get your better 'alf a spangly new machine (or at least a reasonable second hand one) as a belated Christmas / Valentine's / Birthday (early or late) present or she might end up taking her frustrations out on you!
