Hit control/prt scr like you said. Open up paint. (If you have something like Photoshop/Gimp/etc. you can use that instead.) Go to edit and select paste. Save the picture as a .jpg. Go to a free picture hosting site, either photobucket.com or imageshack.com and create an account if you don't have one already. Upload the picture from your computer to the site in your account. Then you can link to it here.
There's no difference between CTRL+PrtScrn and just PrtScrn alone. ALT+PrtScrn lets you copy the screen of the current window or dialog box only (not the surrounding areas). For example, if you press the Windows key, and then ALT+PrtScrn, you will have only the taskbar on memory to paste onto a new image in your favorite imaging software (use Imaging from the accessories menu, or PhotoEditor from Office, and save as GIF for line art or JPG for photography) It's also www.imageshack.us, not .com, and you do not need an account, although it helps to always keep them together. You can always save the link of the files you send if you don't create an account.