Hi Do you mean that your excel files have actually been moved to different locations or that they are opening with picture manager and WordPad.
I suspect that they are opening in these 2 programs and have not actually been moved.
If you right click the Excel file you want to open you will get a drop down menu, In that menu you should see an "Open With" option click that. You will then get a window that says "how do you want to open this file" there will be a couple of options, click the "more options" link and you will then see a list of programs installed on your PC. scroll down until you see Excel and select that by clicking it, follow the prompts and your excel files should all now open in excel.