Hi fotall: welcome to TSG.
From Apple Discussions
Time Machine's FAQ:
To restore a particular file or folder:
With a Finder window open, Enter Time Machine. Locate the item you want to restore in the "cascade" of Finder windows, select it. Now click Restore in the lower right, and TM will put the selected version in the same place it was saved from.
To do a full restore on your Mac:
You need the Leopard or Snow Leopard Install disc that came with your Mac (gray), or any retail (black) Leopard or (white) Snow Leopard disc. It doesn't matter what version it is (and doesn't violate the license if you borrow one), since you won't be loading OSX from it, just using the Installer utility.
Follow these steps:
Boot from the Leopard/Snow Leopard disc. Insert it and either wait for the Mac OS X Install DVD window and click "Install;" or power down, then start up normally while holding down the "C" key, until you hear the DVD drive working. That takes a few minutes.
Then select your language from the list shown.
On the next screen, select Utilities from the top menubar, then Restore from Backups, and follow the on-screen instructions:
You'll be prompted to select the disk where your TM backups are (or search for a Time Capsule). If you're restoring from a disk on an Airport Extreme, click the Airport icon in the Menubar and join the network.
You'll next be prompted to select which of the backups you want, and, if you backed-up multiple drives, which one to restore from. There will be a list showing date & time of each completed backup, and the version of OSX on that backup. Note that the times on the list may not match your current time zone: they may be shown in U.S. Pacific Time.
You're also prompted to select a destination (probably your internal HD), then a confirmation, then the process starts.
If you want to monitor the installation, select Window, then Show Log and Show All logs from the menu bar.
This is obviously a lengthy process, but your Mac will be restored exactly as it was at the time of the backup you selected (unless, of course, you excluded things from TM backups). Then you can just start up normally.
When you do, you should immediately turn Time Machine off, as it's next backup will probably be a full one -- everything it just restored is considered changed and will be backed-up again. You cannot prevent this, only delay it. It will of course take quite a while, and a lot of space on your TM disk, so you may wish to wait until you're sure your system is the way you want it, or even erase your TM disk with Disk Utility and let your backups start anew.
Hope that helps!