Europe Quantitative Easing Okay, this is from latest events. 

Countries like USA &amp; Japan have successfully used QE to stimulate the economy, but what stops European Central Bank from implementing it?

If they decide to use it what will happen to stocks and bonds? How will the investors react? Most economists also say that it wont work well in Europe, why?
Europe is a banking based continent, in contrast to the US where financial markets play a prominent role. As a result, wealth effects in Europe are much smaller than in the US. QE thus has a smaller favorable effect on the economy.

You are right, they should implement it given the low inflation level present for an extended period. But as shown by history, the ECB always reacts later and less agressive than the FED. This is because the ECB has a sole objective of keeping inflation close but below 2% (imposed by the Germans having experienced periodes of hyperinflation). Even today, the germans and some other hawks are still reluctant to pull out the big canon.

QE leads to an increase in bond prices, and supports equities as well. However, whether or not equities go up, depends more on how people react.