Excel Macro Help Needed

I have an excel spreadsheet built, the idea is you copy and paste in data on Sheet 1, it is compared to data on Sheet 2 and the difference is displayed on Sheet 3.

I have put in bold the two entries in Sheet 1 that should be the result of the macro after its ran and of course appear in Sheet 3.

It needs to be able to handle 25k-100k entries on Sheet 2

1. So, in short, the first issue that needs to be fixed, is that it needs to be fixed so it works for me or rebuilt. It needs to be able to handle 25k-100k entries on Sheet 2. It stopped working when I was uploading 5K rows to be compared to 11.5K, although the issue may not have been size related. If you have a better idea, awesome, but I need this to work, and I need it to work fast.

2. I would like to have Sheet 7 created, and this sheet would show all keywords found in a row on Sheet 2., but it would keep the entire row.

Here is the macro that is used:
Sub RunMe()
Dim 1Row, 1row2 As Long
Dim fValue as Range

Sheets("Sheet1").Select
1Row = Range("C2").End(x1Down).Row
1row2 = Sheets("Sheet2").Range("C2").End(x1Down).Row

For Each cell in Range("C2:C" & 1Row)
With Sheets("Sheet2").Range("C2:C" & 1row2)
SetfValue = .Find(cell.Value, LookIn:=x1Values)
If fValue Is Nothing Then
cell.EntireRow.Copy Sheets("Sheet3").Range("A" & Rows.Count).End(x1Up).Offset(1, 0)
End If
End With
Next cell

End Sub