Windows

I recommend that you boot to DOS and rename explorer.exe to explorer.old. Then insert your Windows 98SE and re-install on top of the current version. It will replace your defective version.

There is also the possibility that it is trying to enumerate network connections.
In the Network Neighbourhood properties, select each "Client" (eg, Client for Microsoft Networks, etc.) and click on Properties.
In the Properties dialog, check the Network logon options. It should be set for Quick logon.

Additionally, there are cases where, if a network drive is not available, but has been mapped and set for "Restore this connection", then Explorer will be VERY slow starting up, especially if that drive is unavailable.

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