hello again, this time I know I missed something. Put together a new motherboard, proccessor fan , power supply and windows 7. Hard drive was previously installed in a xp home celeron proc. 478 skt. as a back up. I tried to format while still in machine, but could only delete partition. Hd is wd 250gb . Installed on biostar MCP6PB M2+ motherboard, athlon x2 proccessor. 2 gb crucial mem. and a lite-on dvd writer iHAS124. Power supply is antec 430 watt dual rail. Bios set to cd boot first, gives the post info, recognizes hd & dvd .Screen shows "boot from cd" and then receive disk error please insert system disk and press enter. PLEASE HELP this old fool.