http://forums.steampowered.com/forums/showthread.php?t=2995571&page=3

Just got this problem today. Couldn't launch steam, kept getting steamerrorreport.exe not appearing. Decided to google it after an hour of trying to fix it on my own. An hour later I stumble across this thread after finding a bunch of fixes that I had already attempted. This fix finally worked and I can now login to steam.