I had a Windows 2000 Back Office Small Business Server that developed a problem for no good reason. The Exchange 2000 Pop3 Mail collector failed on start.

The issue was probably caused by a malformed e-mail or spam.

The Exchange 2000 Pop3 Mail collector is a system service so you can access it from Control Panel > Administrative tools > Services.

The only way I could fix it was.

1) Uninstall the Pop3 Collector in Add/Remove Programs for Small Business Server.

Tip: This is about 4 steps into the wizard, so you have hit next a few times. 

2) Delete the Folder C:\Program Files\Microsoft Backoffice\Connectivity\Pop3 Connector.

Tip: I took a Winzip copy of the folder just in case.

3) Re-install the Pop3 Collector.

Tip: Note you will need the CD install Media for this, as it will ask for it.