95 Blazer wont start

4.3 Vortec. Hope some one can help me out. Blazer started fine drove about 30 yds and stalled, unable to re start. Found that spark plug dosn't spark when cranking engine but as soon as the key is moved to the run position the plug fires once. Any idea's?

http://www.automotiveforums.com/vbulletin/showthread.php?t=453370

Besides using the above link, check battery connections.