Old scanned photo's

My wife recently had some old photos scanned but some have turned out very grainy and some very sharp.Is there anything that can be done to enhance them in Elements 6. Its just that I'm new to photoshop and have only just started using it. ANy suggustions or advice would be much appreciated.

Can I also take this oppertunity to wish everyone a Merry Christmas and a happy new year.

Regards
Steve