Excel: Enter date and time formats

To set up a worksheet so that you can enter dates as MMDDYYYY with no slashes between, first click the column header for the column that will contain the dates. Now right-click the column header and select Format Cells from the pop-up menu. On the Number tab choose Custom and enter the following custom format in the Type box: 00\/00\/0000. The forward slash has special meaning in a custom format, so you must precede it with a backslash to tell Excel that you want the literal character, not its special meaning.
Now insert a column just after this column to hold the actual date for use in calculations. Let's say the eight-digit dates were in column A, starting in cell A2. Then you would enter this formula in cell B2 and copy it down the whole column: =DATE(MOD(A2, 10000), TRUNC(A2 / 1000000), MOD(TRUNC(A2 / 10000), 100)). The MOD function returns the remainder when dividing its first argument by its second. Thus the first sub-expression returns the last four digits of your number—the year. For the month, we divide by 1,000,000 and use the TRUNC function to throw away any fractional part. And for the day, we do a combination of the two.
To enter HH:MM time values without the colon, you'll simply use a different custom format. The format 0\:00 will give one- or two-digit hours, while the format 00:\00 will always give you two-digit hours, left-padding with a zero if necessary. A formula like this one would convert the typed value into an actual time value for use in calculations: =TIME(TRUNC(A2/100),MOD(A2,100),0).