When I turn on my PC the monitor doesn't display anything, it doesn't react. It is no grafic-card problem. When I lay my tower on the side it works. But only sometimes! Maybe it is some kind of loose contact, I dunno??? Can you help me???

I presume by this you mean nothing happens the unit doesn't beep. If so it's not XP's fault if the computer won't POST, have you tried reseating everything, CPU, memory, AGP graphics cards come adrift very easily. If that fails take out all your non essential cards.

Hi FlowPopp, I don't see how turning your pc on its side would force any pressure on the vga connection on the back? I think it might just be luck. But in any case, do this first, buy a graphics card. If your straped for cash and time, go to a Staples or office depot or whatever, and get a NVidia brand video card. What kind is up to you, I dont know what you need if for. If it doesnt fix the loose connection, then return the video card, and consider buying a monitor. Are the pins on the monitors cable end all straight? Also, if you can, open your computer up and make sure your video card is FLUSH and ALL THE WAY IN its propper slot. Ok? Might actually be that. L8er.