Software conflicts are an all too common problem for many organisations. The result is usually delays to software roll-outs while time is wasted on testing and fault-fixing.

Now Microsoft and Citrix alliance partner Softricity claims it has a solution: virtualised applications. Its SoftGrid software creates a sandbox, or self-contained execution area, on any Windows NT, XP, 2000 or 2003 PC or Citrix server, allowing each application to run in its own virtual operating space.

"We enable you to run applications on servers or PCs, they run locally but are never installed," says Softricity's European boss Rashied Akrum. "Normally applications install DLLs and write to the registry, we run them without that. We do not touch the OS, and we can't deliver OS-level components, not even Internet Explorer."

He claims that SoftGrid works without the overhead associated with PC emulation programs such as VMware, because it only emulates a small slice of the total operating environment, not the whole machine. It can provide any 32-bit Windows application with a virtual registry and a place to store its DLLs.

This sandbox approach even allows a PC to run different versions of the same application at the same time, for example Microsoft Office 97 and 2003.

"Very much the enterprise's biggest headache is regression testing when an application is replaced," says Akrum. "So you virtualise the applications and then you don't have to worry about them co-existing. It makes application deployment very easy - it's like having a jukebox."

Applications need to be packaged for SoftGrid to distribute, which is done by a sequencing program. The sequencing process typically takes about two hours, and analyses how people use that application so it can be broken down and streamed out over the network as needed.

For example, Softricity's techs have shown that Excel can be launched with just 13 percent of the code, with more being downloaded as the user requests additional functions. The downloaded elements are cached locally, but without ever being installed locally.

For licence management purposes, users must normally authenticate to the SoftGrid server before running an application, even if it is cached, but for mobile users a time-out can be set to give them access to cached software for a number of days while disconnected. This can also be used to give contractors access to company software only for the duration of their contract.

Akrum adds that it works perfectly well on Citrix too, where application clashes can be an even bigger problem: "A lot of applications don't work multi-user, but our software can fool the application that it's running single-user.

"It applies to server apps as well, so you can have a bank of clean servers and deploy them as, say, Webservers when needed. It never touches the OS so they can easily revert. It's the same thing you could do on mainframes 20 years ago.

"People now look at us at the architecture level," he says. "We're bringing a new mindset of deploying and installing. We're not touching the kernel but we're solving some of the things Microsoft hasn't been able to do."