A couple more suggestions...
1) Do you have any anti-virus software running? If so, disable it and try Sub Command. Some have reported trouble with Antivirus before.
2) If that doesn't work, try running SC in windowed mode by taking the following steps:
-Set your Windows color depth to 16-bit in Display Options
-Open properties on your Sub Command shortcut and change "Target" to:
"c:\...\subcommand\subcommand.exe" -windowed
(Include whatever directory you have it installed in, and make sure that
-windowed is outside the quotation marks)
See if either of those works. Good luck!