Windows photo gallery viewer

Hello,
need help ASAP!!!!!! my job and my clientel are ridding on this... my photo gallery viewer isnt working... i can open the main file to see the saved thumbnail pictures but when i click on the photo it self i get nothing but a blank white screen and a message box saying my windows photo gallery viewer unable to start... please dear god someone help me with the fix to this, my job is at risk and im at risk of loosing my clientel if i cant get them there pics... email directly @ Please do not post your @mail (that way u are helping to spread the spam), u will be automatically notified if some one post fresh line in your thread. Thanx : )