LOUVAIN-LA-NEUVE, Belgium — Microsoft Corp. CEO Steve Ballmer offered a glimmer of hope late last week to fans of the company’s Windows XP operating system, saying the company may reconsider its decision to stop selling it soon.

But Ballmer was adamant that most people who buy PCs today buy them with XP’s successor, Vista.

“That’s the statistical truth,” he told reporters at a news conference at Louvain-La-Neuve University. “If customer feedback varies, we can always wake up smarter.”

Fans of XP — the 6-year-old operating system set to be pulled off store shelves by June 30 — have plastered the Internet with blog posts, cartoons and petitions recently. They trumpet its superiority to Vista, whose consumer launch in January was greeted with lukewarm reviews.

Ballmer said the customers buying PCs with XP are corporate information technology departments that are having trouble shifting old machines to newer technology.

Some 160,000 people already have signed an online Save XP Web petition who want Microsoft to keep selling it until the next version of Windows is released, currently targeted for 2010.

On another issue, Ballmer refused to say if the company plans to appeal a fine of 899 million euros ($1.3 billion) that the European Union levied in February.

Microsoft has until the first week of May to launch a legal challenge against the EU decision that it had not obeyed a 2004 antitrust order to share technical information with rivals so that their programs would work better with Windows.

Joking with the media and even breaking into good French, Ballmer acknowledged that he’s finding it hard to keep up with social networking on the Facebook Web site.

“I do have a profile on Facebook,” he said. “It’s hard to keep up. I get many friend requests from people I don’t know.”

“There’s about 10 Steve Ball­mers and I’m only one of them. I’m the one who actually has a picture that looks like me on it!” he said. “I’m hitting a golf ball, that’s the real Steve Ballmer.”

He was in Belgium to open a Microsoft innovation center in the southern city of Mons that hopes to boost new startups in the country, creating some 200 jobs over the next three years.