memory leak?

[gdesreu]

I've been using the following code for a few years to flip spreadsheet data around without issue. Recently however I received a large data set (about 5X larger than those I typically work with and the macro eventually runs out of resources and stops. Typically this runs instantly. I've tried it with screenupdating off and on and it has the same result along with various methods to clear the clipboard after the copy past sequences, they all have the same result. Obviously I have something wrong with my code. I can cut the data set in half and run it twice and it will work but I would prefer to know what is causing the out of resources crash. After a certain number of loops you can watch it get progressively slower each loop until eventually it crashes. Can someone tell me what I am doing wrong with the code below? Thanks

Sub flip()
'paste analytes
Do While Range("W2").Value > 0 
Dim LR
Range("s21:s73").Select 
    Selection.Copy
LR = Range("s" & Rows.Count).End(xlUp).Offset(1, 0).Select 
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
       :=False, Transpose:=False
 
    Range("w21:y73").Select
    Selection.Copy
    Range("s21").End(xlDown).Offset(-52, 1).Select 
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
       :=False, Transpose:=False
       
   Range("w2:w19").Select
    Selection.Copy
HDrng1 = Range("a21").End(xlDown).Offset(1, 0).Row 
HDrng2 = Range("s21").End(xlDown).Offset(0, -1).Row 
HDrange = "(a" & HDrng1 & ":" & "r" & HDrng2 & ")" 
Range(HDrange).Select 
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
       :=False, Transpose:=True
       Columns("w:y").Select 
    Selection.Delete Shift:=xlToLeft
    Range("w2").Select
    Loop
End Sub

 

[gdesreu]

To update the problem and solution. I fixed the issue after closer examination of the file. The file had numerous cells formatted with different colors that I didn't catch at first and even if I did it has never really caused an issue before. It also had numerous cells with different txt formats. Once I removed the formats, my code ran fine on the entire file. (although it took a while) . The code samples above failed as mine did but are more efficient and simpler to use than mine so I plan on adapting these variations. I'm still scratching my head as to why pasting values and deleting the columns with formatted cells crashes excel after a number of loops. I would expect it to get faster as it deletes more records and subsequent formatting but that is not the case. Hopefully someone is about to explain this is detail for future reference so I can better understand it and not do it again but if not, that was what solved the problem in this case.
Thanks guys.