Adobe Acrobat Pro 8.0 - C++ Runtime Error

Hello - I have Adobe Acrobat Pro 8.0 and I have run into a problem that started a couple of days ago.

My computer works fine, but whenever I start Acrobat, after about 5 seconds, it will freeze and give me an error message that reads:

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Runtime Error

Program: C...

This application has requested the Runtime to terminate it in an unusual way.

Please contact the application's support team for more information.

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It will then shut down. I no longer have the original CD, but found that I could download the program at https://www.adobe.com/support/documentation/en/acrobatpro/documentation.html. So, I copied the serial number I found, uninstalled Acrobat Pro 8.0, downloaded the program I found and started the re-installation, but when it asked for the serial number and I put it in, it tells me:

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Invalid Serial Number. This is not a valid serial number. Please go back and re-enter your serial number.

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I don't know if it matters, but I do remember that when I was uninstalling the program, it was telling me something about returning the serial number "e-???". I figured it was returned, but that when I reinstalled the program, I could reuse it.

What are my options to get my Adobe Acrobat Pro 8.0 reinstalled?

I am running with Windows 7.0, Home Edition, Service Pack 1, 3.0 bit.

I am now stuck with no Acrobat and can no longer edit my PDFs. Please help me reinstall this program ASAP.

Sean