From: Computerpilot on 07/09/2002
An older version of a device driver is installed on your computer. This particular error message applies to your VxD Loader device driver. This usually occurs after an upgrade to an older operating system (without complete reformat) or install of a program that replaces the file with an older version.
However it is tough to determine what exactly is causing the problem. You know that the device name is VSYNTHD and I can tell you that it is sound card-related. I think that you have integrated sound with your motherboard.
The first steps I would take is get into windows via Safe Mode. Can you do this? If you cannot, all is lost, start over, do not past go, do not collect $200. I would reinstall the operating system because it will be impossible to edit your settings in DOS/CMD.
If you can get into Safe Mode, uninstall the driver (COMPLETELY REMOVE IT) and reinstall the lastest driver for your sound. Reboot and see if this works.
If not, you need to disable the VSYNTHD from starting at boot. You can accomplish this by adjusting your boot sequence to selective and remove the VSYNTHD the boot up. This will allow your computer to boot normally. However you will loose your sound or a portion of it. You can remove this from your boot sequence in Safe Mode by clicking Start, Programs, Accessories, System Tools, System Information, then click on the tools. There should be an option to change the boot sequence in one of the tools (I can't remember which one, this is different for NT and XP operating systems). SImply uncheck the VSYNTHD item from the list and it will ask you to reboot. Give that a try.
Give a post back if you need more help.