what shoud i do after install it?
any setting?
should i remove the old one?

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what shoud i do after install it?
any setting?

What's it?

should i remove the old one?

What's old?

Pleas feel free to read the manual:
The (very good) manual for Boinc is the BOINC Powered Projects Documentation by Paul D. Buck and the FAQ therein.
A quick installation guide in this is here and for windows go here afterwards.

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Gruesse vom Saenger

For questions about Boinc look in the BOINC-Wiki

If the "old one" was classic SETI, then yes, remove it.

If the "old one" was a previous version of BOINC, you should have removed it before you installed the new one.

So far as the new settings you have available to adjust so the project better suits you, yes, here is a document that gives you some perspective on which things you might want to change and what the choices you have actually mean:

http://www.geocities.com/setinewbiehelp/

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