There's one quick fix you can do yourself. By default, both 95 and 98 attempt to show the system year in two digits. For programs that take the date from the Windows display rather than directly from the BIOS, this can cause a problem. Like the PC, there are several free and commercial programs available to check for problems. If you find a problem, contact the manufacturer for a fix.
Many applications are date-sensitive, as well.
There are the obvious ones, like spreadsheets and money managers, but it's a good idea to check vendor Web sites for updates for all your major applications. Or, you can get a comprehensive Y2K utility that will check all of them. Your data is also at risk. Backing up is always a good idea, but also check to see if you may have created any Y2K problems yourself. In spreadsheets or databases you may be using two-digit years to save time.