Excel file make laptops and computer to much slow and didn't let work on any thing

Could be lots of things. Why is the workbook so large? Do you have a lot of data? How many sheets? How many columns and rows on each sheet? Do you have formulae that are copied all the way down the sheet(s)? Do you have lots of complex formulae or Array formula? Do your formulae use full column references? Do you have lots of formatting or conditional formatting? Is there any VBA code?

If you press Ctrl-End (on each sheet), does Excel select a cell way beyond the real data?

I would start by making a copy of the workbook so you can restore it if necessary.

Then, sheet by sheet, locate the last "real" row of data and go to the first "blank" row. Then press Ctrl-Shift-End to select all the rows to the bottom of the worksheet. The use the Delete icon on the Ribbon to delete all the selected rows. Repeat for the columns; that is, go to the right of the data and select all the "blank" columns. Delete them using the Delete icon. Save the workbook. Repeat for each sheet.

That, hopefully, will get rid of some of the bloat.

I would also clear any Conditional Formatting on each sheet. Maybe reinstate it later if it is important.

You will need to look at the formulae. Perhaps post some examples in the thread so we can assess and advise.

I do one thing, and the sheets work fine now. Excel is running fast on this file now.
Before iterative calculation maximum iterations are 100 and now I change this to 2. Now sheets open quickly than before, and excel was not hanging.

Is there any disadvantage of this please let me know.

Are there circular references in this sheet and iteration is enabled? What kind of problem is the circular reference trying to solve? The main disadvantage to reducing max iterations is that 2 iterations may not be enough for an iterative algorithm to converge on a solution. Long calculation times due to Excel using all 100 iterations may indicate that an iterative algorithm is oscillating or diverging -- which would indicate that whatever the circular reference/iterative calculation is set up to solve may not be resolving correctly (which could mean all kinds of wrong numbers elsewhere in the file).

If reducing the max iterations dramatically speeds up the file, it suggests to me that you need to look at whatever circular reference/iterative calculation is causing Excel to run iterative calculations and determine why that calculation is taking so long.

I'm getting mixed messages from your post. That is the kind of warning you will get if iteration is not enabled. If iteration is not enabled, changing the max iterations should not change anything. If iteration is enabled, then changing the max iterations could easily change the amount of time the file takes to calculate.

I'm not sure how much we can help you at this point. Is the circular reference intentional or accidental? If it is intentional, then one would need to enable iteration and look carefully at the formulas and determine why they take so long to calculate. If it is accidental, then one needs to look at the formulas and determine what was intended and break the circular reference. In either case, it will involve looking at the formulas and understanding what those formulas should be doing. I don't think we will be able to help much without a detailed description of the spreadsheet (and maybe a copy of the spreadsheet). Are you in a position to post a copy of your file (with all confidential information removed/edited?

A difficult position to be in. Here's what I might do:

1) Go to someone in finance and ask them to take enough time to help you understand the circular reference, how it works in the spreadsheet, why it is necessary, etc. If you are going to make any improvements to this spreadsheet, it seems to me that you must be able to understand this circular reference, and they should hopefully be able to help you understand it.
2) Disable iteration and, when the circular reference warning comes up, take careful note of which cell(s) Excel indicates is (are) involved in the iterative calculation. Spend some time with those cells tracking down exactly how the circular logic works. In a large and complex spreadsheet, this can be difficult -- it depends on how much is involved in the circular reference.
3) Re enable iteration with max iterations set to 1 or 2. Repeatedly press F9 and see if you can see the cells involved in the iteration changing. Are they converging on a value, or do they change wildly.
4) Somewhere in step 2, maybe you can see how to separate the circular reference from the large spreadsheet. Extract the calculation into a new file (or build a new sheet from scratch) that contains just the iterative calculation and enough inputs to see what the calculation is doing. This will allow you to see if the iterative calculation by itself is also slow, or if it is only slow in the context of the larger spreadsheet. (In the last post of this thread, I explored a little with how "outside" calculations can dramatically slow an iterative algorithm: https://www.excelforum.com/tips-and-...ml#post4688682 ). This might also be a good starting place for a file to upload to the forum, where you can show us the circular reference and just enough dummy data to represent the rest of the large file for us to see what is going on without violating confidentiality rules.
5) Once you understand what the circular reference is doing, spend some time with the algebra of the problem. I have seen many posts on forums like this where a problem like this could be solved by simply rearranging the problem algebraically to eliminate the circular logic. I recognize that this is sometimes not possible, but it often is.

I am not comfortable privately receiving a file that you cannot suitably anonymize for public posting. However, those are some strategies that I might use to try to figure out what this file is doing.