An exception OE has occurred

I’m running Windows 98 on a pentium 667 with 256 mb of ram. It’s been working fine until this morning when it started giving me the following error message.
An exception OE has occurred at 0028:c001a1aa in VxDndis “01”+0002636
This was called from 0028:c001c3d4 in VxDndis “01”+00004860 It may be possible to continue normally. Press any key.

When I try to continue- it freezes and my only option is to manually shut down the computer. This happened to me a few times today. Besides forthe error message the computer is also working ultra slowly. Do you have any ideas what can be causing these problems and how to resolve it.

Thanks in advance for your help!