Setup Win 98 Question..

I wanted to know, how the Win98 Setup Program checks the Install key... Does it check what YOU enter with a file on the CD or your Hard Drive and either way, how can I find out, how it decides which code are good and which are bad??

I want to know this because I plan on using it in my own program setup....
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nico5038Connect With a Mentor Commented:
Sorry jasinski, but you'll have to code probably your own routine as I mentioned above. Perhaps a web-search might hit a key generator.

Just try a search with modulo-11 and you'll hit probably some banknumber check routines, which could also do the trick for you.
There is no reference to the CD; You can install from a copy on the hard disk after removing the CD.  Also various keys can be used with one CD.

The product key is coded to indicate the type of license purchased.  The setup.exe file is different for upgrade versus full install versions.  The key is validated with some sort of check-sum algorithm and in the case of upgrades validation requires the presence of certain files such as
wait a tick bashley, you mean that you could theoretically make a "upgrade" version a "full" version mearly by entering a CD key of a "full" version or vice versa?
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One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

  As far as I know, there's a checksum test on the number you entered. Mostly you won't be able to use an upgrade version for a full install merely by entering the right serial number, because it's a different program all together (usually, it won't even have all the necessary files for a full install).
However, on a Win 2000 installation, for example, the remote install disk, which is run as an upgrade, and the full install, are on the same disk, and simply run from a different location.

I think the above comments are correct about the chechsum.

For your application this means that you have to create an algorithm like:

First character times 9
Second character times 8
Nineth character times 2

Sum these up and take remainder of sum divided by 11.

This should be the value of the tenth character.

This algoritm can be used in one function to perform both tasks:
1) To check
2) To generate new numbers
The function just calculates the number "to be" by updating the tenth character. When the offered number is to be checked, the result would have to be equal the input value otherwise it's wrong!
The upgrade CD has all the files for a full install, at least in the cases I've tried.
jasinskiAuthor Commented:

--=+ Thanks for your help but, +=--

How can I view this file and find out
how it decodes and encodes...........
Hey I've had a problem that I hate the bundled software that comes with my Aptiva, I purchased the Win98SE hoping to be able to do a full install without having to first install the bundled software (Win98 was bundled with it).

I called up IBM and they quite frankly told me I couldn't install just my OS without putting in all the rest of the software.  So what right? I'll just install it all and then uninstall that which I do not need right?

Well turns out my purchsed CD-R and software and my bundled sound card software, didn't like each other and would often crash.  I was told that I could just put in the Win98SE CD and then at a certain part of the setup it would ask for the old Win98 CD.  Didn't happen.

How did I solve my problem?  I deleted every folder in the root directory of my startup disk besides the Windows folder.  Then took my Win98SE CD and reinstalled the OS and all my other programs.  So far.... no problems.

However, (back to the part related ot the origional question) could I just the OS on a formated drive if I used the CD Key of a CD that is the "full" install?  (As opposed to the "update")

Part of the origional question was "how does it decide" (we answered that with the checksum part)

Still the question remains, "how the Win98 Setup Program checks the Install key... Does it check what YOU enter with a file on the CD or your Hard Drive?"

To answer that question: I believe it would have to be a file on the CD or a file your CD copied to the hard drive (or RAM disk).  If it didn't come from there it would have to come from either DOS or your Boot Disk, so I'm beting on that it checks the CD to see if the number you gave matches with their algorithm.  (Once my little brothers didn't know where to find their CD Key for a game and so they just entered in 1234567890 and it worked)  Sorry for the novel size writing
Boy I just read what I wrote and except for the last part it doesn't make much sense but as to being able to "view" the file, that is probably buried inside the setup.exe executable.  Unless you can do some backwards enginering or something hacking related i'm fairly sure you can't view it at all.  (Besides, if you could so easily piracy would run rampant)
jasinskiAuthor Commented:
I don't know what modulo-11 is but anyway..
It's together with other modulo-"numbers" a checking algorithm for numbers like that for a bank-account.

Normally the last digit of a bank accountnumber is calculated and checked for transactions.
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