Stocks 'n Shares

Boom! Crash!Crunch!(and possibly),Bounce!
It may appear to be the action ''sound-effects'' from a Batman cartoon but in fact these are , unfortunatly, words that are appearing on the banner-headlines of the financial pages in our newspapers.
They tell us that the boom is over(darn , I missed it , again).,that the crash is a possibility,that the credit crunch is biting and the temporary recovery after the intervention of the Federal Reserve was only a ''dead- cat bounce'',( poor, old, Bonny has a lot to answer for...)
So,Guys 'n Gals ,as Jimmy Saville used to say , where do we go from here?
For starters, I'm already confused.Where for example did all those billions disappear to?If a companys' shares were worth ,say,100 units (any currency)at the beginning of June and are only worth ,say, 75 units now,the 25 units has not just disappeared into thin air, somebody must have sold @100 and somebody must have bought @100.So all we need to find out is , where did the guy who sold @100 put his money?........ How did I get into this quagmire?

Anyway it surely proves how we really are living in a Global economy and we are all in it together....whatever it is, and the market never stops.Besides anyone with a bit of savvy must have known that eventually things had to cool down...but I still don't fully understand how the housing market in the USA ,has managed to have such a devastating effect on the world economies.Did the banks and other financial institutions that were buying the 'packages'of credit not actually look inside the packages to see what they contained, (remind me never to accept a 'package' from a financier ,next Christmas....)