7. Resetting your admin password
Forgetting your Administrator password can be a real pain when you want to install a new piece of software or run Apple's Software Update application. If you have a vague idea of what the password is you can try entering it, but if this doesn't work you will have to boot the Mac from the OS X install DVD that came with it, by restarting with the disc inserted in the optical drive whilst holding the [C] key down. Then select Utilities > Reset Password and choose a new one. When you reboot the new password should be working.

8. Detecting a second or external monitor
If you connect a second screen or external monitor but it isn't recognised, try using the Detect Displays button in System Preferences > Displays. The port may be set to use a resolution that the screen doesn't support. If this doesn't help, restart whilst holding down Command+Alt+[P]+[R] until you hear the startup chime twice. This resets the PRAM and often forces the Mac to scan its ports and look again at what is connected. This usually brings the monitor online. It also helps with forcing a Mac to recognise external audio devices.

9. Getting back your lost Airport connection
It's always a pain when you want to work over a wireless network but you can't get a connection. If you lose your WiFi connection, check to see that AirPort hasn't accidentally been switched off. Or, go to System Preferences > Network and, from the AirPort > TCP/IP section, click the button called Renew DHCP Lease, which may fix the problem. Another reason for the loss of signal could be that you have simply wandered out of range of a network, so click the AirPort icon to see if the network is still available. If all else fails, try logging out and in again or even restarting, as this sometimes cures any glitches with AirPort.

10. Fixes for viewing WMV files
The web is awash with video formats and not all of them are particularly Mac friendly. The one you're most likely to encounter is Windows Media Video. Download Flip4Mac, a free codec that enables the QuickTime Player to read WMV files. Alternatively, download the VLC Player from the disc. It can play back many weird and wonderful video formats, though it's not the world's most elegant piece of software. Finally you can install Perian, which provides QuickTime with a raft of codecs to help it open other kinds of videos you may come across.

Update: We have now updated the modifier keys to the correct names. Apologies for the confusion.

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First published in MacFormat, Issue 204

Now read 20 tips to help you work smarter with OS X

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