Are the dark grey areas on the moon formed from the last lava flows from volcanoes? And that is why there are hardly any craters in those dark grey areas because the lava has covered the old craters?And If so are there still active volcanoes that are still flowing to this day?
There was once a very active argument over vulcanism on the Moon - with the distinguished amateur astronomers Patrick Moore and V. A. Firsoff the two leading advocates of vulcanism as having had a decisive impact on the Moon.
The Apollo programme essentially settled this argument as far as craters were concerned - no serious figure seems to doubt these are the result of impacts (though Moore was still forcefully arguing, if knowingly from a losing position, for vulcanism long after the end of Apollo).
For the lunar mare it is not quite so clear cut - it is not disputed that these are flood basalt plains and so are the result of some form of vulcanism. However, they also appear to lie inside impact craters and so there is a suggestion of a connection, at least, with impact.
There are no volcanoes on the Moon today, though there are some signs that there may be very limited vulcanism or similar activity - see http://www.armaghplanet.com/blog/whatever-happened-to-transient-lunar-phenomena.html
The grey areas are known as "maria" (singular:"mare") and they were formed from flood basalts. These are a type of volcano and they have formed on earth too, examples include the lake eruption on Iceland, and the Deccan traps, that played a role in the mass extinction 65 million years ago.
On the moon, the flood basalt is old. About 3-4 billion years old, with some regions probably younger, but nothing less than 1 billion. Volcanism is driven by the heat of radioactive decay. On the moon there are no longer enough radioactive elements to melt rock, and so the moon is no longer a volcanic active body.
There are no active volcanoes on the moon, and there is no prospect of any in the future.