2 Answers

Searching files on a Vista Windows can be done by clicking the 'Start' button (usually is marked with a Windows icon), and then typing the name of the file that is looked for at the search bar, as can be seen at the following picture:
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In Windows XP version, it is done by clicking the 'Start' button, and then choosing the 'Search option that is on the menu that opens, as van be seen at the following picture:
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About you second question, I don't konw if you can undo changes in a webcam video that had been saved. You can try looking for information about it at https://www.google.com.

if your vid was edited from your web cam, { had people in living room ] she made it look as thier was no one ever there at all.now can i but it back to origanl footage