Thunderbird, import emails

[Danesh Daroui <Danesh.D@bredband.net>]

Hi all,

I used to use Thunderbird and now have copied all my email files from on 
PC into another. Now I would like to import my email to new PC which 
have Thunderbird again.
I have copied my emails files from previous PC into new empty folders 
and all email have been retrieved successfully. But in my Inbox I have 
new emails and if I just copy
the old file I will loose my new emails. Does anybody know how can I 
import my email without deleting existing emails in Thunderbird when 
email file already exists?

Regards,

Danesh