This is the Sound Driver 'ESS Mastero 3 PCI Audio (WDM)', and Modem Driver 'ESS ES56CVM-PI Data Fax Modem', that works with the 'Sony PCG-F630 Notebook Computer' for 'Windows 2000'.
The file is identified as a 'Maestro3.comm ES1980 Maestro-3 Audio + ES56CVM-PI Modem'. There are also versions for 'Windows 95/98, Windows 98SE, Windows ME, and Windows NT4.0 on the same web site.
I found this on the 'ESS' web site
I tried several others from other driver sites, but this is the one that worked for me.