Questions
-----------------------------------------
Firstly got Mint on a P4 and the NVidia graphics crash on TF2.
-----------------------------------------
What version of Mint are you using? It used to be that generally speaking most people found nVidia cards worked better than ATI cards. But that situation seems to have changed a bit lately. Bottom Line - you can get lucky with graphics drivers, but it is a common bugbear along with wireless drivers. You will just have to post or search on the relevant forum and someone will probably have had the problem before you and possibly got a workaround. Not sure what TF2 is though, so can't help you there.
----------------------
Not sure where to look for drivers, how to install them, this is the first Linux PC I have had dealings with.
----------------------
Go to 'All>Additional Drivers' in your mint menu. It should detect your basic hardware and give you options for downloading any proprietary drivers it finds for them. 3rd party Graphics and Wireless drivers that can't be distributed with the distro usually. Follow the instructions. Restart. Or you could open the Package Manager or even Software Manager and download from there after ascertaining what exact hardware you have and what drivers go with it. The hardware manufacturers websites are a good place to look for this info. System Profiler from the mint menu should tell you what exact hardware you have.
Or you could open a terminal and type in this command:
lspci (l is a lower case L) lists units connected to PCI
This will pick up your graphics/audio card, inc. ethernet controller/wireless etc..
------------------------------------------
Secondly what is the best way to learn Linux, as an example what is Linux CD, DIR, NET USE, DEL, RD, MD
--------------------------------------
All of those commands are covered in this excellent and concise tutorial -
The 5-Minute Essential Shell Tutorial
http://community.linuxmint.com/tutorial/view/100
Just learn as you go, don't be afraid to search before you ask a question that has been answered a hundred times before. Don't be afraid to ask a question that has never been asked before. Don't be offended when some body is rude to you for asking that question even though you have searched and the question HAS never been asked, let alone answered. The Mint community is a good place to start. They can be a bit indifferent but they aren't as all out brutal as say the Debian forum. Then again, I have had good experiences at the Debian forum. If you show them that you have searched and give them all the info they need and not expect them to be mindreaders, they will at least be civil to you.
Have a look around the Mint forums for your particular distro and read the general F.A.Q.s. There is a wealth of to the point info there. Make use of it.