I installed the QGIS 1.8 a couple of weeks ago and it run ok. Today the qwt5.dll library is missing apparently. I deinstalled and also deinstalled the microsoft visual c++ 2005 distributables to do a clean new install but nothing seems to work.
Windows 7 64 bit .exe
Best Answer
copy the same from
\Quantum GIS Lisboa\bin(installation path) into\Quantum GIS Lisboa\apps\qgis\bin,where your EXE resides....This might help you..:)