sudden slow start of Excel 2003 VBA macro programmes

On my old PC, I ran excel 2003 VBA programmes)with lots of macros) on windows 10 with no problems.
Just got a new Dell 8930 and transferred all this Excel stuff to it.
Now, when I run the same macros, they take much much longer to load.
As an example, a complex one now takes 40seconds to load. A simple one, almost immediately.
In all cases, once loaded, they perform perfectly correctly.
If I reload the complex one 5 minutes later or even after re-booting the PC, it loads immediately.
Strangely, on my Dell XPS13 laptop, which has always had these same Excel programmes loaded,
they also are taking a long time to load.
Both computers are fully up to date with Windows 10 updates.
Help please

Hi Rory - Yes they do

Yes I am. I've changed nothing as far as I'm aware.

After the first load, whether I save it or not before closing, then re-open, it will reload normally. Then I close it. If I then go away and do other things on the PC, then come back to re-open, it then takes ages to load.
However, it seems that if I don't touch the PC after opening and closing it will re-open normally, even if I re-boot the PC.
Still baffled.

Sorry, that last bit about after re-booting is wrong. After a PC re-boot, it again takes ages to load.....

Another piece of information - as I said, the programme takes ages to load after booting / re-booting,
but not after bringing it out of sleep.
After sleep, it loads normally.

I need to clarify what I meant by long time to load.
I click load, and part of the application does load immediately.
(This part is a VBA formatted set of cells with numbers and colours,
and the display of a Userform.
Each cell is a selectable date of the month and the Userform displays text messages for a selected date.
The application is a diary and what seems to be taking the time
is the generation and display in the Userform of the messages for the given date.
The data used to populate the Userform for a given day is derived from a completely separate xls database which is called up from diary's code.
Disabling the macros as you suggested resulted in the immediate generation of the formatted cells, but no Userform.
This is surprising since the cell formatting is done with code which is supposed to be disabled.
I hope this might give better clues as to what's happening.

Before I post the code (which to me with no deep knowledge of VBA coding is probably naive and overly complex)
I will try and remove some recent updates and see what happens.
I will post the results when done.

I removed the windows 2004 update and this reduced the load time from 40 to 20 seconds.
I also found that when bringing the PC out of Sleep, there was no delay,
whilst when booting from shutdown, or on a Restart the delay persisted at 40 secs.
However I had a look at the various modules I had in the "This Workbook" section of the VBA editor
and after "refining them" to provide a simpler start up, the problem would seem to have disappeared.
If this is indeed so, it makes sense, as my other simpler workbooks start immediately.
I'm going to keep this post open for a day or two more just in case, but if things remain OK, I'll close it.
Thanks for all your help rorya - like the dog!

.... error line 3 above ...the delay persisted at 40 secs, should read 20 seconds.

I spoke too soon.
I have 2 workbooks which exhibit the delay problem still.
What I have now found is that the delay seems to start when the code in either of them first hits a "With" instruction.
I made this simple macro and the delay starts when executing the 2nd (Font.Size) line after With Range("Cal").

With Range("Cal")
.Interior.ColorIndex = xlNone
.Font.Size = 12
.Font.ColorIndex = 1
.Font.FontStyle = "Bold"
.ClearContents
End With

The delay is 15 - 18 seconds.
After the delay, it then runs to the end OK.

Curiously, after running the above, the 2 other problem workbooks run without delay.

Any ideas?

Some further information.

Now I find that if I open Excel.exe to a blank spreadsheet,
select Format/Cells (ok so far) then, say, Font, the old delay starts for 15 seconds then,
as before, all is well and other excel apps start immediately.

I have trawled the Internet and tried every suggested solution I can find but none has had any effect whatsoever.

If anyone has any ideas as to why this is, or where I might start to look for a solution I would appreciate it.

I have 2 printers.

One is connected directly to the PC (USB hard wired) and has been turned off during all the problems.

The other is connected via the internet, and again turned off during the problems,
though presumably it's still "connected" to the internet.

Well, finally that seemed to do the trick.
Previously, I had no printer set as the default.
I set the Microsoft XPS document printer as default and now all Excel applications start immediately.
Where the connection between printers and MS Office is I can't imagine.
Just to be sure I'll not sign off as solved for a couple of days, but this time it does look good.
Many thanks again rorya for all your help.