yyinon, welcome to the Seven Forums.
This your motherboard,
GA-K8U (rev. 1.x) - GIGABYTE
If so you aren't going to find any drivers for it. Reason being is that Nvidia bought ULi (maker of the chipset on that motherboard) a few years ago and pretty much turned around and dropped all support for ULi chipsets.
As far the hard drive goes it isn't a driver for the hard drive that is missing, it is a SATA driver that is missing. You basically have 2 options for getting Windows 7 to install,
1. Go into the bios and set the SATA port(s) to IDE mode and then you won't need a driver.
2. Try using the last XP driver for it,
Download ULi Drivers
it also contains a beta Vista driver, only problem with that is not only is the driver a beta it was for one of the Vista beta builds, not even for the RTM version of Vista. If you decide to try #2 you will have to extract the download and then extract the exe inside. Then once you get that far,
1. Place the SATA folder on a separate partition or USB key or burn to CD
2. Begin the install of Windows and when it asks for the SATA driver point it to where you have the SATA folder
3. hope that Windows accepts the driver.
Another problem that you will most likely run into is if you have an AGP video card. Another part of the chipset driver is the AGP/GART driver that is required for an AGP card to be able to install its drivers and function properly. I have a feeling that with that ULi chipset you will run into the same problems that people with nforce 3 chipsets and AGP cards run into (have a search in our graphics forum to see), in that the native Windows AGP driver doesn't support the nforce 3 AGP and as a result they cannot get their AGP video cards to work.
All things considering, despite the fact that your computer is more than capable of running Windows 7, due to the lack of supporting drivers I would at this time stick with XP until such a time as you get a new computer.
