ERROR LOADING SOUND.DRV=MMSOUND.DRV

The drivers may be outdated and you will need to download updated sound card drivers

Open the Control Panel and select Sound Card,then click the remove button

Once you have the updated driver,manually load the sound drivers,by using the Add New Hardware wizard,select the option to select manufacturer from list,then specify the location from floppy disk which you have downloaded from web site.

If you can not get into windows you need to start from a boot disk. You can down load a Win95 or 98 doot disk off the internet. Look to
www.bootdisk.com
or just type in yahoo bootdisk to find what you are looking for.
What is your Windows version? When your computer boots up what dose the screen show?

I agree on "Soulrider"s approach, however, I would go to "Device Manager" to delete the soundcard. Also, MMSOUND.DRV is a Windows file, so when rebooting the system you will be prompted that "new hardware has been found." Place the Windows OS-CD into its drive and make the OS pull its driver from the CD and Replace the existing file.
Good Luck.. IMHO