Problem:
StarCraft on Windows 7 causes a complete lockup of the keyboard, mouse and video, usually around 20 minutes into the game.  Background programs (such as Skype and MSN) still work, but a hard reset is required to recover.

Workaround:
Start StarCraft with a batch file that kills Explorer before launching the game.  The contents below are for an x64 installation of Windows 7.

rem First kill Explorer.exe, which messes up our colors in StarCraft
taskkill /f /IM explorer.exe

rem Change to the StarCraft directory to make sure we run normally!
cd "C:\Program Files (x86)\Starcraft"

rem Please note that /affinity 1 makes sure we only use our first core
rem Using all cores for StarCraft.exe can lead to crashes in Windows 7
cmd.exe /C start /affinity 1 "C:\Program Files (x86)\Starcraft\StarCraft.exe"

rem Wait for the game to quit, press Enter to continue
pause

rem Restart Explorer.exe and WallRotate, that's it!
start explorer.exe
exit

Details/Source:
http://www.evga.com/forums/tm.asp?m=100847055&mpage=1&key=&#100928703
http://www.evga.com/forums/tm.asp?m=100797014&mpage=1&key=?
http://benjaminnitschke.com/2009/06/25/FixingOldDirectX2DGamesInWindows7LikeStarCraft.aspx