I need to reinstall windows 2000 but have lost the microsoft serial
number.Do I need this to reinstall and if so how do I get it without
having to buy a new copy?

Hi highiemack,

    Good day and thanks for your question. I've found the answer to
your question at http://www.thetechguide.com/articles/win2kserial.html

A word of caution though : I don't know how far this method is legal.
If you've bought a genuine Windows 2000 product, I don't think the
following would be morally wrong.

The process :

First you want to copy your Windows 2000 setup files from your CD to
your hard drive. You have to copy at least the I386 directory (I
recommend copying all the files, so you can burn a complete CD later).
Now go into the I386 directory you just copied onto your hard drive.
Find the setupp.ini file. Right click it, select Properties, and
remove the Read-only checkmark. Now open the file to edit it.

Your setupp.ini file should read something like this:

[Pid]
ExtraData=6166656C736263737373B2574A0581
Pid=51873XXX

Replace the 3 X's (generally it'll be three zeros) at the end with
"270". It should now read something like this:

[Pid]
ExtraData=6166656C736263737373B2574A0581
Pid=51873270

That’s it! Now you can now install Windows 2000 without a serial
number!

If you have any clarifications, feel free to ask

Cheers,
aditya2k

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reinstall windows 2000 without serial number

Experience tells me that you do need the serial number