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Exhibit 99.4

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CDW Corporation will file with the Securities and Exchange Commission (the “SEC”), and furnish to its shareholders, a proxy statement soliciting proxies for the meeting of its shareholders to be called with respect to the proposed merger between CDW and Madison Dearborn Partners, LLC. CDW SHAREHOLDERS ARE ADVISED TO READ THE PROXY STATEMENT WHEN IT IS FINALIZED AND DISTRIBUTED TO THEM BECAUSE IT WILL CONTAIN IMPORTANT INFORMATION. CDW shareholders and other interested parties will be able to obtain, without charge, a copy of the proxy statement (when available) and other relevant documents filed with the SEC from the SEC’s website at http://www.sec.gov. CDW shareholders and other interested parties will also be able to obtain, without charge, a copy of the proxy statement (when available) and other relevant documents by directing a request by mail or telephone to CDW Corporation, 200 N. Milwaukee Ave., Vernon Hills, Illinois 60061, Attention: Corporate Secretary, telephone: (847) 465-6000, or from CDW’s website, http://www.cdw.com.
CDW and certain of its directors, executive officers and other members of management and employees may, under SEC rules, be deemed to be “participants” in the solicitation of proxies from shareholders of CDW with respect to the proposed merger. Information regarding the persons who may be considered “participants” in the solicitation of proxies will be set forth in CDW’s proxy statement relating to the proposed merger when it is filed with the SEC. Information regarding certain of these persons and their beneficial ownership of CDW common stock as of March 31, 2007 is also set forth in CDW’s proxy statement for its 2007 Annual Meeting of Shareholders, which was filed with the SEC on April 16, 2007.
Statements about the expected timing, completion and effects of the proposed merger between CDW and Madison Dearborn Partners, LLC, and all other statements in this filing other than historical facts, constitute forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Readers are cautioned not to place undue reliance on these forward-looking statements, each of which is qualified in its entirety by reference to the following cautionary statements. Forward-looking statements speak only as of the date hereof and are based on current expectations and involve a number of assumptions, risks and uncertainties that could cause actual results to differ materially from those projected in the forward-looking statements. CDW may not be able to complete the proposed merger because of a number of factors, including, among other things, the failure to obtain shareholder approval, the failure of financing or the failure to satisfy other closing conditions. Other risks and uncertainties that may affect forward-looking statements are described in the reports filed by CDW with the SEC under the Securities Exchange Act of 1934, as amended, including without limitation CDW’s Annual Report on Form 10-K for the year ended December 31, 2006.