Hi All, After a bit of help to find out if it's Windows 7, the computer or the HD that is the issue. I am upgrading my old 80gb Hitachi HDD in my lappy to a 320GB WD Black. I changed the HDD over in the caddy for a fresh install of Windows 7(64bit) (old HDD uses Vista). The Bios recognizes the NEW WD HDD and the install disk boots to the accept terms screen for the NEW OS and then the system freezes. I did this three times and everything the same thing happened. I put the old HDD back in with vista installed and all is well again. The guy helping me works in our IT dept and he seems to know his stuff and it has him stumped. The spec of my machine is Acer 5720, Intel Core 2 T7300 (2.0ghz, 800mhz FSB, 4mb L2 cashe), plus 2gb DDR2 RAM thinking that it might be my motherboard that is somehow preventing the install due to compatibility problems?My friend thinks that the HD might have a problem with it?Any help you can offer would be greatly appreciated, because the only alternative I have is to send it back and exchange it for a new one and try again, but I would like to think that I have exhausted all the other avenues before i did this, especially as there might be a quick fix or reason why I am getting this repeat fault.