First try this

Go to Start | Run
Type in rgsvr32 advapi32.dll

If that doesn't work
Go to Start | Run
Type in SFC
press OK
(You may need your Windows 98 disk)

Click Extract one file from installation disk

Specify the system file you would like to restore box,

type drive:\windows\path\file
(where drive:is the drive where the Windows folder is installed, generally drive C,
path is the destination of the file that you are extracting, and file is the file that you want to extract).

In this case you will want to extract oemig50 to C:\Program Files\Outlook Express

click Browse next to the Restore from box, and then locate the Windows installation files.
(By default, in the OEM version of Windows 98 and Windows 98 Second Edition the installation files are on the hard disk in the C:\Cabs folder.)

With a retail full version or upgrade version, you can also insert the Windows installation CD-ROM into the CD-ROM drive or DVD-ROM drive, and then locate the Windows installation files. The folder is named "Win9x". For example, if your CD-ROM or DVD-ROM drive is D:, the folder is named "D:\Win9x". For Windows 98, the folder is named D:\Win98

Click OK

Finally if that fails remove Outlook Express from your startup folder
Go to Start | Run
Type in Msconfig and click the Startup tab
Uncheck Outlook Express and restart your computer

Of all the Things I've lost, I miss my mind the most