My HD crashed (Windows XP on a 7-year old computer). I have an almost new 1TB Western Digital HD (empty, but partitioned into 3), and another, newer desktop running Win7. I thought that I could just copy that desktop HD with its OS onto the Western Digital, plop it into the bad computer, and run with it. NOT. Now I understand (correct if wrong), I need special cloning software to do this (versus running out and buying Windows7). Okay, let's say this is the correct step. So the next question would be, after plugging the "cloned" HD into the bad computer, what are my next steps? I think I read somewhere something about entering the BIOS??? PLEASE, SOMEONE HELP. Also, is there going to be any problems running Win7 on a 7-year old computer? It currently has 2x 512MB DDR, and capable of up to two more for a total of 2GB. Pentium 4 running 800mHz. THANK YOU in advance.