I have two general replies and than a specific qustion.
1) Does WS 7 have an installer log similiar to the one in Linux?. If so please post it - it could be in a temp directory. Try using a search tool like locate32 to search something like vm*.log. If such does not why does it not VMware?
2) What exactly IS error 1920? I'll guess that VMware has a glossary of their error codes but if they are proprietary why not just emit "unknown error" or "unknown internal error". and not emit a specific code to the user who can't use the information
To your paticular problem. Have you tried using a dedicated uninstaller program to remove WS 7?. I like revouninstaller (freeware or shareware) because in "advanced" mode it creates a system restore point before running the native installer/uninstaller program and then its own (VMware does NOT).. You will find well in excess of 100 leftovers after WS 7 is "uninstalled." .There does exist a KB article about how to completely remove WS iin Windows (I think 1308) but some have said it doesn't work. Maybe you can't do this to corporate policy - this doesn't seem likely but I can't say.