Class not registered

I have Vista home basic and can not open anything without getting
class not registered message.When trying to open control panel I get
message that reads 'c:\windows\system32\explorer frame .dll is eithe
not designed to run on windows or it contains an error.Try installin
the program again using the original installation media or contac
system admin." And when try to open pictures,documents etc it say
"class not registered". Someone previously in this forum had the exac
same problem and said they went to "download and restore missing o
deleted dll files" at dll central.com but did not mention what file t
download. Can anyone please help

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jay975