If you suspect the caps, you (or a tech) might be able to replace them. But, after 20 years, it can be any other component.
You might be able to find another machine running Windows 98 or capable to run it on freecycle or such, if this one can't be fixed. It's only 2 years ago I dumped mine (which had a motherboard I bought in 2003 or 2004, and still functioned perfectly).
Kees
I think I am in deep trouble, but maybe someone can make it less painful. I have a W98 SE system on an old 33 MHz X4 machine which has always worked flawlessly (about 20 years). I set it up to run my accounting package and to prevent outside access this machine is not connected to the internet or a network. It is a stand-alone machine with QB Pro 5.0 on it and a ZIP drive for weekly backup. My regular work- a- day machine has W7 64-bit loaded. As fate would have it the W98 machine failed to boot today and the monitor displays a "No Signal" message. It also does not sound like the OS is loading.
I am also unable to load QB Pro on my W7 machine since it is a 16 or 32-bit program. Ideally I would like to get the W98 machine operating again, but the mobo may have two bad caps (slight bulging at the top). My guess is a new mobo would not recognise the old equipment and OS.
Can anyone help?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic