how to eliminate duplicates.

Hi,

I'm okay at vba but I'm still a novice. I find that I can do stuff in small pieces but when I try to add them all together I lose my way.
Basically what I'm trying to create is an account sheet that totals everything my company is spending its money
on each month. What I have is data that comes in four columns. The columns are Date of purchase, company name, amount and balance.

So basically I load the data into sheet 1.

Then what I want to do is this:

Load data into sheet1

Then copy this data and put a copy(not cut and paste) of it in sheet 2. This is so I have a record of everything that is being used in the account sheet.

However this is the tricky bit. When I take the data from sheet 1 and copy it to sheet2 I want it to do a specific duplicates check. So lets say I have 5 rows of the data. An two rows of this data are duplicates of what I've used before. What I want to do is have the 5 rows of data in sheet 1 to be checked against all the other data I've copied to sheet 2 in the past. I then want it remove the two rows of duplicates. leaving only the three unique rows in sheet1.

I understand how to copy data to sheet 2 and I understand how to remove duplicates on sheet 2. But what I can't work out how to is to check data from the rows of data in sheet 1 to the data in sheet 2 I copied in the past. An then remove the duplicates leaving the unique data in sheet 1.

Cheers guys any help is appreciated. I'm talking ideas as well as code all welcome.

Post either a sample workbook, or your code