Thank you for the information you have provided.
When I enter gcc -v I get the following response:
gcc version 4.3.2 (Debian 4.3.2-1.1)
this appears to confirm that my kernel was compiled using gcc 4.3.
To me it looks like you've upgraded your kernel to a newer version compiled with gcc 4.3, but your system still has 4.1 installed.
I assure you that I would not have a clue how to go about upgrading my kernel. Also, as indicated in my last posting, I cannot find any files on my system that include the characters "gcc 4.1" in any part of the filename, which seems to indicate that I don't have gcc 4.1 on my system.
So it would appear that my system has been compiled using gcc 4.3, but I dont know why the nvidia installer wants to use gcc 4.1. It looks as if the nvidia installer is expecting to find gcc 4.1 on my system for some reason. I have looked on the internet* and I have found several 64 bit nvidia drivers for my graphic card. They all have different file names, so I am assuming that they are different to each other in some way. All of them appear to have been created in mid to late 2008. Perhaps gcc 4.1 was the most recent version of the compiler at that time so that is why the compiler expects to find it?
For your information, I only installed Debian 5.0 about two weeks ago. I do not have internet* access on my personal PC, so I purchased the complete set of 5 Debian 5.0 AMD 64 DVDs from a Debian certified site. My version of Debian was installed from those DVDs. It is my understanding that these 5 DVDs give me access to the entire repository of Debian packages, although I cannot confirm this. If my understanding is correct, then I should be able to install the packages you refer to, although as I need to do this from my DVDs and not via the internet, it is likely that updating the package list will have no effect.
* In case these two points sound contradictory, I do not have internet access on my own PC but I can access the internet from public terminals, and occasionally I can use a friend's PC that is connected.
1. Purge any previously installed nVidia packages.
I am not sure how to do this, but I assume that it requires me to uninstall any nvidia packages that I have added to me PC. I will read up on how to do this, the research will be good for me, and I will see what happens. If all else fails I will just reinstall Debian from the DVDs. I know that this is usually only recommended as a last resort, but it will mean that my system will be working properly within about 60 minutes. This should restore the X server, and likewise my GUI interface; I will then be able to run the package manager then take the other steps that you suggested.