This all looks very hopeful. I need some help from you, though.
First, how do I confirm, from my hardware, the particular chipset that my board uses? The motherboard user manual makes no mention of the Intel chipset series. The only reason I mentioned 5 Series before was because that's what comes up when I analyse the IDE Controller driver in Device Manager. But, of course, that'll only be there from my having installed Gigabyte's driver. Although my board is ostensibly a P55, that's a bit of a misnomer as it actually uses only an H55 chip. There's no onboard graphics chip.
Now to the driver, etc at that URL. Just to confirm: is it the second one down in the list that I need? The one called "INF Update Utility - Primarily for Intel 6,5,4,3, 900 Series chipsets, v.9.2.0.1025, dated 3/3/2011"? Further, is that the actual file, or is it just a downloader/installer (the webpage makes a distinction between "Software Archives" and "Utilities, Tools and Examples"? The description "utility" is confusing me. For the INF driver and its installation, do I need anything else? I don't use RAID/AHCI, I'm just using the SATA hard drive in IDE mode.
Are the INF and Realtek LAN files designed to be installed over the top of the existing ones, or should the existing ones be uninstalled first (especially since what I already have, in the case of the INF file, is the Gigabyte version)?
Gigabyte's offerings, as regards drivers, are bewildering, as currently their INF driver seems to be well out of date and yet their PCIe LAN driver is, apparently, completely up to date (v.5.782). Actually, during the installation of Gigabyte's INF driver, you're told that it's only a beta version!
I may have a window of opportunity shortly for installing the board's drivers completely from scratch, cleanly, as I may be buying a new hard drive and installing everything from ground zero again. I need a reserve SATA hard drive, anyway. I do have means to backup and restore complete partitions but there's odd rubbish on the existing drive that I want to completely eradicate anyway. Clearly, if I invest in a further drive and install everything from the bottom up, I'd want to be fairly assured that using the recommended chipset drivers will eliminate the remaining 'accessing problems' I've described.
Another afterthought: I've returned to that Intel webpage several times now, to read all its assocoated notes. I don't think that installing this particular INF file is going to make any difference at all to the strange hard disk and floppy disc drive problems I've been experiencing. I'd previously assumed that this was an INF file that also contained an IDE driver, but from what I read there, this is literally the INF and nothing else. It merely inserts the appropriate device name into Device Manager, nothing more. On reflection, I think this probably accounts for why Gigabyte's version of the file is so old, namely that the naming of a few devices is actually not going to change much as time moves on.
It would appear that the board doesn't require any IDE or graphics drivers at all. Either that, or they're being somehow automatically obtained from Windows.