I am using win7 and I have the ToH soundfront posted in this thread. I think my problem may be related to those in the other thread saying that it crashes after 2 seconds since I have similar symptoms. I installed virtualmidisynth and SS:EE on my laptop and it works perfectly, not sure why my desktop doesn't agree.
When I uninstall virtualmidisynth on my desktop SS:EE no longer crashes. Can't figure out why they won't play nice on my desktop because my laptop has no issues.
How much RAM does your laptop have? As long as it's more than 2GB you should be good. Make sure that the Soundfont is selected in the VirtualSynth configuration, make sure that the mapper is set to VirtualSynth, try setting your output device from default to the output device you are using. Also, turn off the check for Increase Process Priority to REALTIME. That might be a big issue.
There could be an issue with the soundfont you downloaded, as in maybe it is corrupt. VirtualSynth will not tell you if it is, so it might cause crashing. Try with a very small soundfont first to make sure the driver is working. Here's a decent one, it's a rip of the SoundBlaster AWE64: [url=http://www.alsa-project.org/~james/sound-fonts/8MBGMSFX.SF2]http://www.alsa-project.org/~james/sound-fonts/8MBGMSFX.SF2[/url]
When using a small soundfont you can uncheck the option of having the whole soundfont pre-loaded just in case that is what's causing you problems.
Your audio set up might not be configured for 48000 Hz audio. If that's the case, you can tell VirtualSynth to output to a sample rate of 44100Hz (CD quality).
If you get sick of testing in VirtualSynth, you can always try BASSMIDI. VirtualSynth has worked a lot better for me every time, but if you can't figure it out, BASSMIDI is worth a shot.
Here's some advanced instructions about BASSMIDI from systemshock.net https://www.systemshock.org/index.php?topic=3188.0