The machines, which were launched in Tokyo by Michael Dell, are designed to take up less space on the desk than ordinary computers and can be placed either horizontally or vertically.
An optional LCD monitor is available with a companion bracket that acts as the monitor stand and does double duty as a stand for the main PC, so the two will take up even less desk space.
Dell has taken out features such as PCI or AGP slots, so users will not be able to connect their own graphics boards or other add-in cards such as SCSI adapters. Instead, Dell has chosen Intel's 845G chipset which includes integrated graphics.
There is also no floppy disk drive as standard but the machines are the first OptiPlex line models that support booting from Universal Serial Bus (USB) memory keys. Dell said it planned to launch such a device next month and that it expected the higher reliability and storage capacity to make such modules more popular than floppy disks for booting machines.
Should users want a floppy drive, the computer's hot-swappable media bay accepts the same modules as Dell's Latitude C range of notebook computers.
Users have the choice of Intel Pentium 4 or Celeron processor and up to 2Gbytes of double data rate (DDR) synchronous dynamic RAM (SDRAM). Other technical features include six USB 2.0 ports (two front and four rear), integrated AC97 audio and integrated Intel Extreme graphics support.
The cheapest OptiPlex SX260 costs $599 (£387) but a typical system will come nearer to $1,499 (£969). This machine includes an Intel Pentium 4 processor running at 2GHz, 256Mbytes of DDR SDRAM, 20Gbyte hard disk drive, 24X CD-ROM drive, Intel Gigabit Ethernet networking adapter and a 15in LCD monitor.