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C++/Debug Assertion Failed!


Hi!  Please forgive me if I am asking the wrong Expert, but I really don't understand your expertise.  But I'll ask you anyway.  I have windows 98 and Microsoft Internet Explorer.  On some webpages (not all of them), when I try to enter things (like a search word, or my name to register) I will immediately get the following message:

Debug Assertion Failed!
Expression:_BLOCK_TYPE_IS_VALID(pHead->nBlock Use)
For information on how your program can cause an assertion failure, see the Visual C++ documentation on assets.
(Press retry to debug the application)
abort       retry       ignore

It really doesn't matter which one I press because all of them eventually kick me out of the internet.  
Can you tell me what is wrong with my computer and how I can fix it?  Please keep in mind that I am not very computer smart. Even my kids (aged 21 and 18), whom I consider to be experts, don't know what to do about this.  My son's computer is networked with ours, and he does not have this problem.  

Two of the web pages that I have this problem with are (when I try to do a search for recipes using a particular ingredient) and (when I try to register to personalize a cruise)

I am hoping that you will be able to help, but if this is not your expertise, please forgive me!
I eagerly await your answer!  Thanks!

Gail Timmermans

Gail Timmermans, Thank you for your question.

I suggest that you also post this question in the Windows section of

The error message you are getting is a last-ditch attempt by Windows to help software developers find a problem that was not detected in any normal way.

Because of this, the message is cryptic and unhelpful.

I would recommend that you remove (using Add/Remove Programs in the Control Panel, which can be accessed from the Settings item in the Start menu) your browser (presumably Internet Explorer), then download and install Internet Explorer from

If this does not solve the problem, you will probably have to reinstall Windows from your Windows disk(s). Instructions for doing this are contained in the documentation of your computer or of Windows. If you cannot find written documentation, look at the folder on your Windows disk for a file named Readme.

David Spector


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David Spector


Highly knowledgeable in the C++ language, Visual C++ (MSVC), Windows API, documentation and other quality-assurance techniques, and debugging. Knowledgeable in MFC, COM, GUI design, and object-oriented design.


I have been a software engineer since 1965. I have been published. My specializations have been: biomedical programming, compiler implementation, and many kinds of Windows programming. I don't do Databases or other business-oriented stuff.

Windows?/DOS Developer's Journal, ACM SIGPLAN Notices, and Computer Science Press.

ICCP Systems Programming Certification
Master's degree equivalent in Computer Science

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