Microsoft on Friday expanded its refurbishing rules to benefit companies who want to refurbish and re-sell their old PCs to new customers.

The Microsoft Authorized Refurbisher (MAR) program is an offshoot of its current Community MAR, which is designed for charities, educational institutions and nonprofits.

"Companies don't know what to do with their old PCs, so they collect dust in the company cafeteria or stack up in the hallways," Hani Shakeel, senior product manager of the Genuine Windows Product Marketing team said in a statement. "This is a very common fate for PCs these days, especially with the increased environmental regulations around the disposal of computers."

Microsoft said it is offering a new license for refurbishers that is only available through the MAR program. Windows XP Home for Refurbished PCs and Windows XP Professional for Refurbished PCs are the two operating systems available and the PCs that are being refurbished need to have a Certificate of Authenticity.

In 2004, Microsoft conducted a joint study with Gartner that focused on the secondary market, Shakeel noted. What the company found was 150 million PCs of which about 20 million were refurbished and then resold. Currently, Microsoft is projecting that 28 million PCs make up the refurbished market -- an estimated 10% slice of the worldwide PC market pie.

But even with the increase in renovated desktop and laptop computers, Microsoft's partners complained that they did not have the recovery media or recovery image for a PC. The only way to restore the original image was to go back to the OEM and order replacement media.

So, instead of transferring the software license from the original owner, Microsoft said it would tweak its volume licensing and allow for genuine versions of Windows on the refurbished PCs.

"Essentially, they're restoring the PC to its original state when it was first shipped from the manufacturer," Shakeel said.

In May, InformationWeek surveyed 630 IT professionals about their experiences buying secondhand IT equipment. Nearly half of those polled purchased secondhand equipment regularly and more than half of those who did said they had a very satisfactory experience.

The extended program is currently open to Microsoft's A-list OEM friends worldwide and to other refurbishing partners in North America.