Removing page cache...how to remove temporary internet files in ASP.net

Hi, I m using this code to set expire of asp.net pages.it is workin fine in if the client datetime is same as server date time but if the clients machine's system datetime is not proper or like if clients machine datetime is 4 months back then server machines then the cache remains in the clients machine also in case of windows  XP cache does'nt removes automatically..

Response.Buffer = True
        Dim dtExpire As Date
        dtExpire = "#January 01,1978 23:59:59#"
        Response.ExpiresAbsolute = dtExpire         'DateTime.Now.AddDays(-1D)
        Response.Expires = -15000
        Response.CacheControl = "no-cache"
        Response.Cache.SetCacheability(HttpC ...