Ok, I'm back, now.
I'm not done, yet, but I'd like to reply to YoKenny's question.
I have 4 x 512MB DDR2 RAM installed.
More to come after the reinstallation.
I'm still waiting for some motivation to begin this procedure.
EDIT:
I forgot to ask...
Shouldn't I reboot, too, after the uninstallation, but before the new installation?
EDIT2:
Damn it! I forgot to ask something else.
On my computer there's a 2nd power switch.
By using that switch, I can boot this computer into a special multimedia mode.
In this mode, a Linux version of PowerCinema is loaded without the need of booting into Windows.
In order for the computer to work like that, that Linux version edited the MBR somehow, when it was installed.
Now, I wonder, what will happen to the MBR, when I run the uninstall-utility?
Will it destroy those special settings?
Will it affect the MBR, anyway?