You shouldn't need to redownload the setup file. Normally I'd suggest rebooting, shutting down all non-essential programs (such as anti-virus) and reinstalling the game again. However, there is an update for the GOG version (and the anthology / DVD version) that hasn't gotten an official patch yet (
music fix), which would replace the div.exe file anyway.
Of course if the div.exe was corrupted during/after installation, it is possible other files were, as well, so if the music fix doesn't get the game working I'd try another clean install.
If you want to check that the setup file is ok, the
GOG Community Wiki lists the md5 checksum values for many games there (the md5 value for setup_divine_divinity_1.0.2.13.exe is d9cfa77cb5f2da6be9c6c2a7a90da653. You can use a program like
Hash to create an md5 value for the file you downloaded, and check it against the expected value.
File: setup_divine_divinity_1.0.2.13.exe
Size: 1970463719 bytes
MD5: D9CFA77CB5F2DA6BE9C6C2A7A90DA653
SHA1: E416BB5822838DD1FF9931D9039EC9BF78149670
CRC32: 44443E0F
If you continue to have file corruption problems with DD, or have had problems with other resource intensive programs (burning DVD-Rs, etc), you may want to check your system RAM, or run ScanDisk on your hard drive (right click on the hard drive in Windows Explorer, select Properties, switch to the Tools tab, and hit the Check Now button in the Error Checking Status section).
Memtest86 /
MS Windows Memory Diagnostic