The color of selection elements in themes used by Ubuntu 12.04 is determined by a single value and is therefore the same for all of them: highlightened buttons, files, menu items as well as the selection box that you get by holding and dragging your mouse.
You can set this value in the settings.ini of each theme. The settings file of the Ambiance theme for example is located in /usr/share/themes/Ambiance/gtk-3.0
Before you edit the file, create a backup copy of it in case you want to reset the theme to its original state. Just copy the file somewhere else to do that. Afterwards, open the original file as administrator. This is easily done using the terminal:
sudo gedit /usr/share/themes/Ambiance/gtk-3.0/settings.ini
The value that determines selection color is nselected_bg_color - it is formated as hexadecimal value (#000000). You can now use a graphic editor to find out the hexadecimal value of the color you want to use - if you wanted to use red for example, you would have the value #FF0000.
Afterwards save the file and log out of your current session. After the next login, all elements of selection should now have the color of your choice:
It may occur that when you try to copy files from your hard disk to an external device such as an external HDD or a USB key, you get an error stating that there was no free space left on your device although you just erased everything from it to make some. This is most likely due to limitations of the file system your drive uses - newer drives might already use the NTFS file system while older will still use FAT32 or even FAT16.
The thing is that FAT32 formatted drives only support files up to a maximum size of 4GB - for example if you try to put an image file of 6 GB onto an external, FAT32 formatted hard drive of 320 GB with 100 GB of those still free and not in use, the copying will fail. To change this, you have to format the target drive to the NTFS file system.
Formatting will erase all data on a drive, so backup everything you have on it beforehand. Afterwards, right-click the drive in your file browser and choose Format....
On the appearing window, there will likely be an FAT file system on the File System drop-down menu (if it already says NTFS there, this guide won't solve your problems). Before you change anything, double-check that you picked the right drive. Then change the file system to NTFS and click Start.
If you look for a powerful tool to move files to FTP or SFTP servers or want to move them via SCP on Windows, there is a valuable solution for you called WinSCP. WinSCP is a useful Client able to deal with files in all three ways and comes with an easy-to-understand graphical user interface. You can download it >here<
Just log yourself in with the receiving server's data, choose the protocol you want to use and you will be presented with a two-framed window that lets you drag and drop files between the servers:
HiJackThis is a software that is able to detect unusual entries on your registry and hard drive and create a log file with the information it gathered about the running processes. This log file can either be analysed by the user himself or be copied into an automatic analyser that shows if the entries are rated safe or dangerous.
You can download HiJackThis here: http://www.trendmicro.com/ftp/products/hijackthis/HiJackThis.msi
If you made the program create a log file after scanning, it is recommended to copy and paste it into an automatic analyser such as the one you can find here: http://www.hijackthis.de/en. The analyser will then give you an overview of the scanned files combined with a rating given by visitors.
If you find any unsafe entries, you are given the option to fix them in the program's window. Be cautious what you delete however, inform yourself about the stated entries and do not rely on information provided by a single source. Always double-check before you delete an entry.
If you have ever tried to set another default application for opening file folders on Windows XP and to turn it back afterwards, you will have run into a really nasty bug.
If you try to restore the default settings of an application to open a folder, the folder will no longer open as before (normal explorer window, further folders open in the same window) but will open a search window on doubleclick.
You cannot achieve the former behaviour by trying to reset it in the control panel. What you have to do is to create a new opening action for File Folder and set it as default. Afterwards, open Run... and enter regedit to open the Windows Registry. On the left side of the registry, there is a list of directories. Browse this list to HKEY_CLASSES_ROOT > Directory > shell and click on the plus-button next to shell to unfold the actions to open file folders with. Now look for the new opening action you have previously created and set as default. Rightclick it, choose Delete and confirm your choice. It is not enough to delete this entry in the Control Panel, it has to be done in the registry. Close the registry after deletion and try out doubleclicking a folder. It should now open like it usually used to.
To encrypt folders on Linux Ubuntu there is a simple program called Cryptkeeper which, while active, lets you mount and dismount password protected folders.
While unmounted, the encrypted folders are invisible to the user. While mounted, you need to enter the password to access its contents. To create a new encrypted folder just click on the key icon on the system panel and select New encrypted folder.
Make sure to unmount the encrypted folders before you quit Cryptkeeper since the files become accessible if they are mounted and Cryptkeeper is inactive. The files remain invisible if they are unmounted and Cryptkeeper is quit.