Motherboard: FUJITSU SIEMENS MS-7293 1.00

The only mode I could find in my BIOS was ACPI, which I guess is powerrelated, and a RAID function which was Disabled.

EDIT: Yes, ACPI is indeed power related.

Are the HDDs in SATA mode or IDE mode? You could possibly try switching them to IDE if possible.

The only option I could find in BIOS was IDE or RAID. I don't really think setting them to RAID would be a good idea.

Could be I'm looking in the wrong place.

I also tested the Vista installer. Same problem there. Though this helps a lot, since it shows that any solution for Vista problems are likely solutions to the same problem, and will therefore work with Windows 7.

I don't doubt that it is a BIOS problem now. I just need to conjure up the right way to deal with it...

I had the same problem a while back. It turned out to be a known bug in the Windows installer. If two identical drives are connected and one of them is unpartitioned (or something like that, I don't recall the exact specifics), then the Windows installer won't detect any of the drives. The solution was to physically remove one of the drives, install Windows, and then reconnect the drive. There's a Knowledgebase article about this problem at microsoft.com.

This is also a known problem when trying to install onto drives that have been used with Linux or in a RAID/NAS configuration. If that is the case you may need to low-level format the drives using utility software from the manufacturers website.

As for the monitor problem, a proper monitor .inf file should solve the problem. There should be one on the CD that came with your monitor.

I have tried all possible HDD setups (2 big ones, 1 big 1 small, 1 big), but it might be I never formated any of them properly... I could try setting one of them up with an extra partition, just to see if anything happens.

None of them have been used as RAID or with Linux. I don't know what NAS is, so I'm guessing that's not a problem either.

As for the monitor, about the third thing I did was to install the driver for the monitor that I got from the developer homepage. I also updated my Nvidia drivers, tried other drivers on random, and tried to force the resolution from a third party software.

Two things I have yet to try on that front is to buy a new (and possibly better) DVi>VGA adapter and install an older version of the NVidia drivers.

But that's all for tomorrow. I'm going to go to bed now.
Thanks for the support, people.

Actually system thing is very simple.

When you put new HDD you most probably haven't  changed HDD drive priority (which tells computer in which it should start looking for OS).

For now i think you should :

a) put both HDDs into computer

b) go to bios and make sure that Sata mode is set to IDE

c) check HDD boot priority so the first one is the drive you want to use as your OS drive.

I tried step a) through c) without sucess :(

I'm about to give up and buy a new motherboard.

I finally solved both problems. Here's how I did it.

I bought a new Motherboard, and I bought a new Videocard. A Radeon card this time.

Now I have Windows 7 installed and I am playing games in full resolution.