I have a sharepoint 2010 portal. I have a farm, with inside of it some site collections. One of these site collections ok. I would like to create a new site collection and restore a backup of the old site collection. How can I do this?
The best way to do this is via SharePoint 2010 Management Shell: http://www.bradleyschacht.com/backup-and-restore-sharepoint-2010-site-collection-with-powershell/
Or you can take a backup of Site Collection in Central Administration tool and restore it using Management Shell/PowerShell: http://blogen.siderys.com/2010/02/how-to-do-backup-and-restore-in.html
There is not just one way to do this and you could use custom tools. BTW some useful links:
I have already answered the same question several times...
Try o see this one.
Hope it helps you,
You can use stsadm or directly bacpup-spsite command from powershell.
run as admin mode
for more info pls check Site collection Backup and restore command