A deal is being negotiated between Whitehall and Microsoft to try and stop thousands of NHS computers becoming vulnerable to hackers following the April 8 cut off date for support.
The Department of Health told The Register that it is currently in talks to develop a plan which would see its PCs migrating off from Windows XP.
The NHS in England runs Windows XP on just over one million computers, with NHS Scotland having just 3,603 PCs running the expiring operating system.
Official Microsoft support ends on 8 April, when the firm will stop issuing security patches to block malicious code that can infect PCs with viruses and even steal data.
Security expert Graham Cluley told CBR that the threat to Windows XP machines is very tangible.
"It is very likely that online criminals will attempt to exploit unpatched vulnerabilities on the XP platform," said Cluley.
"Typically the most attractive vulnerabilities will be remote code execution vulnerabilities which can be used by malware such as a Trojan horse or worm to infect your computer.
"Anyone continuing to run Windows XP after April is, in my opinion, playing a dangerous game."
After 8 April, users who want to continue having Microsoft protection must pay up to £120 per desktop for year one, £240 for year two and £490 in year three.
The Register was told that negotiations should "conclude shortly", with the Department of Health commenting that they are "discussing plans with Microsoft for putting in place a migration plan and extended support for the NHS."