I want to compute some indicators based on price movements in the component stocks of the S&P 100. I would like to be able to compute these for the past 6-7 years for backtesting. However, some of the stocks that have been removed from the index have merged or otherwise no longer trade under the same symbol. In some cases, the symbol has been reissued to a new company. Is there somewhere that I can find historical EOD data on stocks where the symbol is no longer being used or is being used by a different company now? Some examples include MEDI (Medimmune), G (Gillette Co.), and MAY (May Dept Stores).