LCD brightness — IBM TP390!!!

Laptop in question is TP390e with Win98SE on clean installation (done about a year ago) without the proprietary IBM utilities. I want to brighten the screen. Have it set in BIOS for maximum brightness — which makes no discernable diference — but have seen no setting in Windows for adjusting brightness. There is a manual slider on the bezel which seems loose and does nothing. The screen is passable but dim compared to other laptops especially in bright light. It will go brighter; for instance on a restart it will step up to a nice bright level just before shutting down Windows. Any suggestions? By the way, will be upgrading to W2KPro soon — any chance that will provide a solution? Thanks!