Zdroj: http://answers.ea.com/t5/Crysis-2/error-code-1638/ td-p/312188/page/4I can confirm that this works.
Start regedit
Edit>Find> type crysis2
Delete HKEY_LOCAL_MACHINE/SOFTWARE/CLASSES/INSTALLER/PROD UCTS/"random_numbers%letters"
I just installed the game. Before that I tried and got error code 1638.