DateTime format with Entity Framework

Can someone explain how it works? I need compare a DateTime in SQL Server with an user input.

Here an example of what I'm looking for:

DateTime[] dates = { DateTime.Now, DateTime.UtcNow };
Console.WriteLine(dates.Where(x => x < DateTime.Now));    // I need to know if they are the same without converting them to strings. 
Console.Read();

I'm using Entity Framework and in the entity class Dates, the attributes are DateTime and I need to compare that with a user's input, and the only solution I found was the CreateDate function.

As you know, I cannot compare the POST value directly with a Date attribute. Example:

db.dates.Where(x => x.StartDate < "2012-02-13 00:00:00.000")    // error, cannot compare DateTime with string

So, I tried converting the value to DateTime:

DateTime start_date = Convert.ToDateTime("2012-02-13 00:00:00.000");
db.dates.Where(x => x.StartDate < start_date )    // PROBLEM!!

Why? Well, the output of start_date is:

2012-02-13 12:00:00 am

But in the database, the end and start date are as follows:

2012-02-13 00:00:00.000    // all have zeros at the end

How can I compare the date when the input date is in 2012-02-13 00:00:00.000 format?

I don't care what to use, I just need the same format and the same data type.