When you say Flat Screen I presume you mean LCD/TFT (TFT is a type of LCD monitor)? It's a really stupid name as I've seen plenty of Flat Screen CRTs.
As Bisc. says on the Settings tab from the Properties window it will say Screen Resolution, you can also see what your colour depth is set to (it should be set to 24-Bit or 32-Bit regardless of your monitor/graphics card). As far as PC's go:
640x480 - Still used in computer games but otherwise very much dead. Very old, no detail or sharpness and massive icons.
800x600 - A bit better but not by much.
1024x768 - Pretty much the standard but slowly dying as Monitors get larger and TFTs get sharper.
1152x864 - Where sharpness starts to become acceptable.
1280x1024 - I lie this is what my monitor is set to. TFTs don't go much higher than this at the 17" level.
1600x1200 - Commonly available on CRTs but I've yet to find anyone who uses it. Tiny icons but very sharp.
There are also lots of other non-standard resolutions which change from monitor to monitor and graphics card to graphics card but they usually don't give you a 4:3 ratio.
You really don't want to go lower than 1024x768. If your monitor is less I really recommend going higher, putting up with the smaller icons for a day (it will bug you at first) and you'll quickly get used to it.
Try setting the resolution higher to get an idea of how much sharper things can get (Windows XP won't let you choose by default an option your monitor doesn't support and even if it goes wrong after 10 seconds if you don't click on OK it reverts back).
FYI the icons will get smaller as the dots have to get smaller to accommodate the extra dots which give you the shaper image.
BiscLimpkit wrote:right click on your desktop background/wallpaper, click on properties then settings.
The amount of people who call this the Screen Saver is staggering. Oddly I've yet to find someone who calls their Screen Saver the Desktop.
FYI it's the Desktop, the actual picture is your Wallpaper.
Just like technically it's the picture that is the icon, the icon as most people know it is a shortcut. I gave up ages ago calling it by the proper name and use icon now too.
People who call their PC the Hard Drive cracks me up too. Why I don't know as you won't ever find IT Guys calling a PC the Hard Drive or rarely even hear them use the word period around end-users.
BiscLimpkit wrote:Dammit romero, that was my idea. Now everyone's gonna credit you cos you came out with a funny example. :x

I saw you said it first
The thing is that defeats the point of a Comparison forum in some ways. Links would work too at the end of the day.