Windows won’t boot

Running a P4 3ghz system w/Asrock mb, 512MB ram, wd hard drive. Will not boot into windows, locks. Tried running CD for recovery console, gets to “Windows is starting” and locks. Swapped out memory, cd drive, cd, hard drive, still locks at “staring windows.” Set BIOS to defaults, cleared CMOS, same problem. Any ideas????? Thanks.