Archive files are basically containers of a number of other files, which make transportation and/or storage easier. They may also be compressed, meaning that they take up less room.
You are probably familiar with .zip files. This is the most popular archive format. Winzip is a popular program, which can create and unpack .zip files. However, Winzip cannot open many of the other archive formats. The same can be said for Winrar and .rar files, or Winace and .ace files, and so on. What's more, these are all commercial programs that cost money.
There is good news: IZArc is an excellent, free archive utility, supporting nearly 60 archive formats, such as: 7-ZIP, A, ACE, ARC, ARJ, B64, BH, BIN, BZ2, BZA, C2D, CAB, CDI, CPIO, DEB, ENC, GCA, GZ, GZA, HA, IMG, ISO, JAR, LHA, LIB, LZH, MDF, MBF, MIM, NRG, PAK, PDI, PK3, RAR, RPM, TAR, TAZ, TBZ, TGZ, TZ, UUE, WAR, XXE, YZ1, Z, ZIP, ZOO.
Why would anyone buy Winzip, Winrar, Winace etc.? I don't know. You can replace all of these programs with IZArc. Do it now.