Windows 8 isn’t being adopted by PC users in the numbers Microsoft had hoped. Though the company has sold 60 million Windows 8 licenses, the new OS still holds a marginal share of the desktop OS market, while Windows 7 and XP make up over 84% of the market.

Normally when software (or hardware, for that matter) isn’t selling is the time when most companies consider a price cut to match the low demand for the product. Microsoft isn’t most companies.

Starting tomorrow, Microsoft will be increasing the price of Windows 8 upgrades, giving customers another reason not to upgrade.

Since the release of Windows 8 in October, Microsoft has been selling Windows 8 Pro upgrades at the “special price” of $40. Starting February 1, an upgrade to Windows 8 Pro will cost PC users $200. Even the upgrade to the normal Windows 8 edition will cost $120. Students with a .edu email address will be able to buy the Windows 8 Pro upgrade for $70.

Microsoft has also been selling the “Pro Pack,” which upgrades regular Windows 8 to Windows 8 Pro, for $70. That upgrade will cost $100 tomorrow. Also, the Windows Media Center upgrade pack that is currently being given away for free to anyone with Windows 8 Pro will cost $10 tomorrow.

Microsoft hasn’t commented on whether prices for stand-alone versions of Windows 8 will be increasing in price tomorrow. If not, that would mean that simply buying a copy of Windows 8 OEM for $140 (or regular the regular Windows 8 OEM for $100) would be far less expensive than upgrading from Windows 7.