Make absolutely sure you have the "jumper" on the correct pins, check in your manual/handbook. Turn PC off and remove the plug from the wall socket. Make sure the "jumper" is on the correct pins for normal operation. Now, remove the battery that keeps bios running its about the size of a 10 pence piece. Leave it out for about 10 minutes and then replace. Plug back in and try and get into the bios by "tapping" the del key or some other key? If you can get into the bios, then make sure your "boot order" is set correctly to boot from your HDD with the operating system on it.