I just saw this problem when visiting Google.com using IE10 on Windows 8:
Notice the missing search box. You can’t see it in this screen grab, but the cursor is blinking and the form input is actually there. Typing a phrase in a clicking “Google Search” gives the proper results. You just can’t see what you are typing in. Clearing the browser cache did work, so it must have been some corrupted css in the cache. If you are having the problem, hope this works for you.
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