I have a dell PC brand new that I have BROUGHT to europe. can anyone give recommendations on change of power supply for both main and screen, as well as the speakers? Can the power supply simply be swapped out? And would a cord change AND voltage change be neccessary for the screen? I am in Greece and need a fairl detailed response as Ihave to TRANSLATE and my Greek isnt that good. Thanks.Greece is 220VAC 50Hz

Changing the computer should be quite easy:
1.  Move red button on back of power supply from 110 to 220.
2.  Obtain IEC power cord with proper plug for Greece.  The end that plugs into the computer is the same as the 120VAC power cord.

The montor may just need the same power cord.  Look on the back of the MONITOR for the nameplate.  It will show the voltage range, mostly likely 100-240VAC 50/60Hz

Look at power brick for speakers.  You may need a different one or an adapter.  If speakers are powered from monitor (some newer ones are), nothing else to do.
Some Power Supply Units are auto-switching. If yours has no switch, you will have to review the manual.