Your printer should work. Here is a link to Openprinting, the best source of information for printers.
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http://www.openprinting.org/show_pri...amsung-CLP-300
It lists the driver known to work. You will need Cups installed, what ever distro you settle on.
Basically jumping around will get you no where but frustrated. Pick one and install it. I suggest you go with one that has an easy to use package manager, and is commonly used. I see you have tried a few already.
As for the printer, after you install your OS, install cups. It is available for all distros. Then follow the information on Openprinting to install the driver. Once that is done, you need to open up a web browser, and on the location bar type:
http://localhost:631 press enter. That will connect you to the cups interface. Become root, and add a printer. If the driver is installed, then you will find it in the list of drivers. Pick the correct one. At the end of it you can run Testpage to verify the printer is now working.
On the modem, I would need more information. RT w'less doesn't tell me much. Please input the full maker name, model etc. If you have a wireless modem, then you probably have a wireless card in the system. To get that all working, we need to know what card you have. Open a konsole, and run the command '/sbin/lspci' ( without the quotes ) and post the results. That may help us find out what card you have. Then we need to track down a driver, ( if one exists ). Install the driver, configure etc.
Wireless can be difficult. The fact that they work on MS tells us the hardware is O.K. only. It is a good start, but we have a ways to go.
BTW, I'm a 60 year old fart... been at this for a while...