Could it really have been a corrupted download twice in a row?
The zip file has checksum, if the file is broken the unzip or winrar detects that and shows error message. WinRAR should have a test function that shows downloaded file matches the checksum. If the checksum matches you have an intact and complete zip file.
Did you download from the links on this page under the Download -heading?
Verify disk has free space for the game, 13 GB for the download and another 13 GB to unpack the zip file.
If you have same problem with another game, too, maybe your new computer is faulty. Try for example running memory test to see RAM works correctly. Try Internet Search engines with “memory test” or maybe MemTest64 or similar tool.