I bought a computer from PC Specialist and it hasn't worked properly from the very beginning. It started from the difficulties with the installation of the software. The technician spent here 7 hours but didn't manage to make some devices work properly. The memory diagnostic tool found a hardware problem and asked to contact the manufacturers. They changed the RAM. But the problem was still there. Windows kept crashing and various applications kept closing. Then they took it to the service centre to repair. They returned it saying that there had been some wrong settings on the computer. But the computer didn't start working normally. Windows kept crashing with the messages "check if hardware or software was installed properly". When I complained again they suggested that I had a software problem and suggested reinstalling Windows. I have Windows 7 Ultimate 64 bit. They sent a guide how to reinstall Windows and I did. They also suggested reinstalling the motherboard driver and the graphic card. After I reinstalled Windows and started reinstalling Asus driver Windows recovery message appeared. A bit later DNS Client stopped working. So these were the signals that my actions haven't solved the problem. The company refuses to take the computer back and return my money saying that it is a software problem. I am not sure it is a software problem. How can I find out? I ran the memory scan, it didn't find anything, I ran the hard disc scan last night, it didn't seem to have detected anything. When Windows started I got 5 messages "Desktop Window Manager has stopped working and was closed". The computer sometimes produces a strange tinking noise. So I can see the computer is going to perform badly as before. Is this the software or hardware problem now?