Monitor's are not "upgradeable", they are hardware, some have profiles (inf files) which some refer as "drivers". I do not see a reason you can not use the monitor with 98se. What you may be having a problem with is the video display driver, there is a physical video card installed into the case or built on to the motherboard. This may cause some problems.
What OS were you using before? Windows 95?
You did not say if the monitor does not display anything when plugged into a system running Windows 98se. What leads you to believe it will not work.