Wal-Mart and Best Buy attracted plenty of buyers for laptops during a promotional offering of laptops priced under $300. Some of those laptops sold out just one day after the offers began. The prices were respectable considering the generous features, including large screens, better graphics and DVD drives, which are not typically found in most low-cost netbooks today.

However, the laptops came preloaded with the Windows Vista Home Basic OS, which does not include a free upgrade to Windows 7 in the U.S. Instead, consumers will have to shell out about $120 to upgrade the operating system.

Mainstream laptop prices have dipped under the $300 mark just a few times over the past few years. Last week Best Buy initiated a price war by offering a fully equipped Acer laptop for less than $300. Wal-Mart responded by selling a $298 Compaq Presario CQ60-419WM from Hewlett-Packard. Best Buy soon countered by offering for $298 Toshiba's Satellite L305-S5955, which is still available on the retailer's .

Many potential buyers left questions on Wal-Mart's Web site asking if the laptop was eligible for a free upgrade to Windows 7. Vista has been panned by critics for being sluggish and resource-hungry. Windows 7, due for release on Oct. 22, has been praised by beta testers as faster and more efficient.

Retailers are still offering many inexpensive PCs that aren't eligible for a free upgrade to Windows 7. Best Buy and Wal-Mart are still offering many inexpensive netbooks, laptops and all-in-one PCs from Acer, Gateway and other PC makers preloaded with Windows Vista Home Basic.