Okay, I do not know exactly what is going on but I called my father and he told me what happend. A few days ago I had a Sony VAIO (I do not know the exact model but it a very popular series a black desktop with a hole in the middle if you know that one). My father brought in another Sony VAIO but an upgrade of this one. He wanted to switch them because he needed firewire so I agreed cuz this one was awesome (3.4 with 2 gigs or RAM!). My father swapped the harddisks from the computers cuz he wanted to keep the original data. But the problem is he accidentaly took out the harddist with the operating system. Now when I turn this computer on it says something like reboot... (no operating system what do you expect?). I asked my father to install XP on it so I can use it. In a few days I call to ask for progress. He said that XP installations starts but after it starts the computer says "unable to find harddisk-something like that". But there is a harddisk in the computer! I offered my suggestion that maybe this other harddisk in not recognized by the computer as the master harddisk, but do not know if that is right. Help us please.