Microsoft will no longer provide security updates for Windows XP beginning April 8th.
That means computers running on XP -- and even machines like ATMs -- will be largely unprotected against viruses and cyber attacks.
Experts say that could easily expose businesses that don't upgrade to a new operating system to cyber attacks.
Microsoft won't say how many small businesses currently use Windows XP.
But Forrester research estimates about six percent of companies' PCs will still be using it by the April deadline.