[X-Newbies] Corrupt mail application?

[Carole Wessel]

I am running Mail 1.3.11 on my G5 10.3.9

Dear team, I hope you can help me

In the last few days the mail application seems to be corrupted:
- Either it looks for ever for mail (grey circle turns and turns) 
eventually stops and then I can't read half of them.
- Or, the one I have just read disappear from my in-box, and then the 
grey circle turns and turns...
- If the computer goes to sleep, same thing, and the mails that I've 
read come back with the blue mark for unread, or the deleted ones 
reappear.
- Then, sometimes I have the beach ball for ever and I have to force 
quit
To go faster I have to go to my 2 accounts directly through the web 
(Verizon & AOL).

What should I do? Just tried to read the discussions on the Apple 
Support discussions, and there are pages and pages of mail problems... 
none seem to be like mine.

Should I reinstall the application? I already backed up my mail folder.

Merci,
Carole