Why does Pages 09 hang for 1min30sec? The spinning ball, etc...

Question

I am using Pages 09 version 4.3 (not the iWork package, just Pages 09)
Operating system 10.8.3 with 4 Gb memory on an iMac from around 2009 (Intel core 2 duo)
I had been using Quark Xpress for a couple decades and wanted to save a book I did in Pages so I can sell it in the Apple bookstore.
So I saved a Quark document as a pdf.
Then I used an on-line service to convert the pdf to a word document.
Then I opened the word doc in Pages and saved it as a Pages file.
I am in the process of doing a lot of reformatting, but I'm not surprised all the formatting didn't carry over, considering all the flie formats I went through.
The document is about 40 pages and has perhaps 40 pictures, but I do resize them in Photoshop so the Pages document file is only 4.9 Mb.
Pages isn't all that different from Quark, it just seems to hide things in different places.
The problem is that every so often when I click in the document, I get the spinning ball and Pages hangs for 1 minute and 30 seconds (doesn't it seem odd that it is always for the same length of time?). Then it comes out of its coma and I carry on.
Using the Activity Monitor I see Pages using 99.8% or 100% or even 100.5% of CPU. And The Pages line is in red type that reads "Pages (Not Responding).
While I wait for Pages to come to its senses, I can surf the Web, or use other programs, which seems peculiar because if the CPU is 100% occupied, I would think it could.
When I go to the dock and click on the Pages icon, it doesn't come to the front. I have to move any other windows so I can see my Pages document and click on it to bring it to the front.
I went into FontBook and checked all my fonts and deleted a bunch. When I reopened the document, it said it was missing a font, so I selected a substitute, the document opened and I re-saved it with a new name.
Sometimes it hangs when I click in text, but just now it was hanging every time I tried to click on a line behind the main text box.
Just now it hung when I started to go to the Edit menu. I waited and now it's back, as if nothing happened.
Any ideas?

Answer 1

After a very long night it seems my problems were solved by
1. making sure all the in-line pictures had the correct wrap around settings and
2. deleting some lines that had originally been underscores, but wound up being independent lines behind the main text box and
3. checking my fonts in FontBook and deleting the iffy ones (I dunno if this made any real difference, but I mention it anyway).
Every time I would select a line there would be a long pause. Initially 1 1/2 minutes, but shorter as I deleted the lines one by one.
There were also pauses when trying to select in-line pictures, and sometimes for no good reason that i could discern.
Anyway, now that the pictures' wrap around is re-set, and the lines are delected, there are bo more pauses!
Whew. I spent hours watching that ball spin. Still, it was better than re-creating the whole book.