Your FAQ says:
I used different email addresses with different projects.

This could be a problem. The email address is part of the algorithm to match a user across projects. If the email address differs, you might have two BOINCstats accounts that won't merge.

This can only be solved by going to all projects and make sure the same email address is used for all projects.

I did this. All my projects has now the same info.
We are now 10 days later, but I have one CPID
3ddbeee86859b094ea4aa2f3d1ba381c and one CPID
db50b9a6ed6a7bbc2573c5d478a508fc.
They will not merge. How can I merge account Ynze Bicknese with account ynze bicknese? Now I lost 25000 credits!
Maybe anyone can help me?
Thanks!
Ynze.

The other common question for one in your situation is do you have one computer that is attached to all projects? (Even if it can't run all of them.) This helps to co-ordinate CPID's

Yes, I have 2 computers. They run all projects.
I lost my password for account Ynze Bicknese, so how can I get my credits for this account to account ynze bicknese (no capitals)?
The project Climate Prediction knows my new account (with no capitals) so when I download some work from it, it starts by 0 credits.
The Einstein project knows also my new account, but on 1 computer I have 8,762.32 credits, on the other 0 credits. I use BAM as accountmanager.
For Climate prediction had I 17,249.44 credits.
How can I save this, en make my account ynze bicknese the only account in BOINC (and BAM)?

Basically you can't. If you have duplicate accounts on the projects they can not be combined. I advise that you use the one that is associated with BAM! and change the details on the other one to make it unusable.