Just a quick note. The .inf file you quoted your computer as using to install drivers is the same one you say it later says is missing.
This kind of thing can be quite common and can be caused by the .inf file being written a certain way (e.g. to look in certain locations for files or because of a slight mistake).
If you get the message that X file can't be found at this location you can either look in the disk/folder you got the driver from, your windows/system.. folders or run find and search for it. Once you have found it you can then browse to the location when the popup tells you it can't find it and offers the browse dialog (sometimes you have to let it try a couple of times before it offers this).
The above goes when your installing new drivers as well and you can often get by without using the windows CD for example, if you don't have it to hand, when it asks for it using this method. In fact I had to use this method when installing the vga drivers that came with a friends Nvidia based motherboard the other day because the supplied install exe (install shield) wouldn't work properly and the .inf decided that the windows CD was where some of the nvidia drivers should have been.
As for your AGP always going back to 2X can't you just go into your motherboard BIOS, by pressing Delete during booting perhaps, and set it to 1X there? When set from there it shouldn't be able to reset itself to 2X. Unless of course this has been mentioned to you already and I haven't noticed it or the card won't work unless it gets to boot at 2X.