A Miami-based system integrator that's selling an unauthorized Mac clone called Open Computer has closed its online store.

Psystar, on its Web site Wednesday, said its Internet store is closed because "we are currently unable to process any credit card transactions." Psystar did not provide an explanation for the problem, which it called temporary.

Despite the closure of its online store, Psystar is continuing to advertise its Mac clone.

One version of Psystar's Open Computer features Apple's Leopard OS X 10.5 operating system ported onto generic PC hardware that includes an Intel Core2Duo processor at 2.66 GHz, a 250 GB hard drive and an Nvidia GeForce 8600 GT graphics card.

The system is priced at $804.99. A similar, Apple-branded computer would cost more than $2,000.

But would-be buyers can't order an Open Computer due to the apparent failure of Psystar's e-commerce system.

Psystar said it's fulfilling orders placed before its credit card processing system went down. "For customers who have already placed orders: if you received a confirmation e-mail then your item is in queue to be built and shipped," says a note on the company's site.

Psystar changed the name of its Mac clone from OpenMac to Open Computer earlier this week -- perhaps in response to anticipated legal pressure from Apple. Apple's end user license agreement forbids the installation or use of Leopard on third party hardware.

Business records show that Psystar is a small company operated by Miami residents Rodolfo Pedraza and Roberto Pedraza.

On Monday, a Psystar representative who would identify himself only as "Robert" said the company is not concerned about legal action by Apple. "We're not breaking any laws," Robert insisted in a telephone interview.

Psystar may be willing to have its right to sell Mac clones tested in court, Robert implied. "What if Microsoft said you could only install Windows on Dell computers?" he said. "What if Honda said that, after you buy their car, you could only drive it on the roads they said you could?" he added.

Robert also accused Apple of marking up the hardware on which its operating systems run by as much as 80%.

Psystar's Web site was up and running as of Wednesday afternoon -- except for the online store portion. The site was offline earlier this week as news of the company's Mac clone spread across the Internet.