Any ideea why every NSIS setup file(.exe) i download gives CRC error when trying to install. I do not have any firewall installed and also i tried with and withouth a download manager. Also files downloaded with bittorrent have crc errors. But this happens only with setups that were made with NSIS and only on windows 7, on XP they work fine and aloso any other files work except those made with NSIS.
Maybe you have a file virus which inserts itself into executables between downloading and execution. Try uploading one of the corrupted files to Virustotal for scanning.