The Problem
Lag spikes have been an increasing issue as Minecraft has become a more in-depth game, and though it was originally acceptable if the player accidentally placed two blocks instead of the one they wanted once every few hours on older computers, it has now grown so extreme that players have found themselves placing up to four blocks each time they click. Until now, there has been no solution.

Finally, I decided that this had to end. Going back to AutoHotkey, a macroing software I last used over a year ago, I compiled a 22-line script that finally solved this problem.

Using the Program
1. Extract the .zip file to an easily accessible location
2. Before starting or while running Minecraft, run BlockFix.exe
3. To close BlockFix, right-click on the green 'H' icon (the AutoHotkey logo) and select exit.

Problems/Known Bugs
* Occasionally, clicking on the buttons in the main menu ceases to work; simply restart BlockFix to solve it.
* Sometimes clicking will freeze, the solution is as above
* While this has never happened to me before, it is possible that BlockFix could freeze, in which case there are several alternative ways of closing BlockFix.

1. On Windows 7 or Windows Vista, press ctrl+shift+esc to open Task Manager, find BlockFix.exe in the processes (keyboard may be necessary) and force quit it. I have never had an issue with force quitting.
   
2. On Windows XP (and older) press ctrl+alt+del to open Task Manager. Do as for Windows 7/Vista.
   
3. Force shut down the computer by pressing and holding power button (not advised!).
   
4. On Windows 7 or Vista, press ctrl+alt+del and select 'log off'. Log on again, and BlockFix will have closed.
   
5. On Windows XP (and older) press 'windows', then 'u' or 'l' (to shut down or log off) and repeat the key again to confirm
   

If any other issues arise, send me a message.