I had similar questions when i first got here a few years ago. I'll add a little to Refalm's statements
1. Games. Can a linux OS handle and run a demanding game such as UT2k4?
Yes, Linux (Operating systems) can handle intense graphics. Linux OS's can produce better results more quickly, provided that certain conditions are met:
A) The game has a Linux port. You wouldn't try to run a windows program natively on a mac, you would use a mac program. This is the same case. To get a game to run, see if it has a Linux port (UT2k4, Doom3, Neverwinter Nights are the three i play natively).
B) 'A' above is not entirely correct. If it does not have a linux port then your best option is to use Cedega (
http://www.transgaming.com). A $5 program that lets you run windows programs in linux by translating the Windows API into Linux API and Directx into OpenGL. There is a slight performace hit, and check transgaming's compatibility list. Hey... it's 5/month for a subscription and I use it to play World of Warcraft and Warcraft 3, although many others work.
c) It is best if you have a good graphics card. This is obvious. Good graphics cards for Linux include nVidia Geforce cards. ATI is not necessarily a good graphics card producer, as their drivers suck ass
2. I know GIMP is available for linux, but for my purposes, it would not be sufficient. Can linux run Photoshop?
Linux can run Photoshop, but not natively. Similar to Cedega (formerly called WineX, since it was derived from Wine) above, a program called Wine (
http://www.winehq.com) can run windows programs. Wine focuses on WinAPI --> LinuxAPI, and doesn't do anything with Directx as far as I'm aware of. It is free, too.
3. Can I have multiple OS's on one PC? Is it a good idea?
Yup. all you need is a seperate hard drive. Don't have a seperate hard drive free? then make a partition on one with some open space. I usually give my operating systems (ya...plural) at least 20gb each, but that is up to you.
During the install of the Linux operating system, it will install a Bootloader. This bootloader will give you the option to load either Linux or Windows every time you bootup your computer. GRUB is the most common bootloader used nowadays
If you don't like that method, then you can not bother with it and make a floppy bootdisk if your computer has a floppy drive.