zipped
.rar
You can no longer view these files, but they will take up less space on your hard drive. If you want to view them again, just unzip it (pretty much the same way you zipped it). Compressing files is good for sending them to someone, or if you need more space on your hard drive. It gets smaller.
you can find ds emulators and game files on coolrom.com
PCSX and PCSX2 are the emulators available for MAC computers. These files help the MAC computer read the PS2 games and run them effectively on the computer.
When files containing large amounts of information are compressed or zipped, they are moved and forced into a smaller space to conserve memory and protect the file(s).
Compressed files are often named colloquially after the software used to consolidate them. Common names include Rars, and Winzips for these file archives.
Although many files these days do come in zipped files it is extremely easy to unzip the files. One of the oldest and best known programs for doing this is a program called WinZip.
Nintendo DS ROM's or read only memory files, are files that are used to play games on simulated consoles known as emulators. In other words, these files work as versions of games from other consoles like the Nintendo Entertainment System, Super Nintendo, Sega Genesis, and so on.
if it was from the ourpcgame.blogspot thingy site, then there should be a file inside the zipped folder that says "readme". so read it!!
Compressed (zipped)
It is very easy to unzip files. Firstly you need to download the zipped file,and save it to your computer. You can download programs from cnet, which will allow you to automatically unzip compressed files.