When I try to install crossover, the Sofware Center instructs me to place Ubuntu cd in drive and then continue. As I Installed Ubuntu via usb flash drive, I have nothing to put in cd drive. How can I have the Software Center use the usb drive?
Tried to simply plug the installation-USB-stick in, mount it(double click on the desktop icon that appears...can also be in the side-bar...you'll see the contents of your USB-Stick if mounted successful) and than execute the software-center and tried the installation again...if that works it is able to read the installation USB-stick based, "OS-disk".
If not or already tried out, you'll may have to get a disk-image...even if the PC don't reads it at boot, it normally reads it in the installed Linux system...otherwise I worked around that by using my USB-DVD-RW-drive or changing the internal one, to one from LG that has no problems with Linux disks.