Troubleshoot virtual PCs that are not operational in XP PAE mode

Under XP installed virtual PC Run is the following prompts:

Virtual PC cannot run in PAE mode

This version of Virtual PC cannot run in PAE (Physical Address Extension) mode. Please revert to normal state to run virtual PC

Explain:

Physical Address Extension (PAE) overview

Physical Address Extension (PAE) X86 allows software to use the Address window extensions (AWE) API set and run on computers with Intel Pentium Pro or later processors, while more than 4 GB of physical memory allows more physical memory to be mapped to the application's virtual address space.

Applications that do not use an AWE API set can also benefit from PAE X86, as the operating system improves performance by using larger physical memory to reduce pages. Similarly, this also benefits the merged servers that host multiple applications.

By saving data in memory rather than on disk, you can improve the performance of applications that manipulate large amounts of data.

Update to PAE X86

The following updates have been performed to support increased data Execution Protection (DEP) (also known as non-performing page protection):

When you enable DEP on a computer with a processor that supports non-performing page protection features, PAE is automatically enabled on computers running Windows Server 2003 with Service Pack 1 and Windows XP with Service Pack 2.

When PAE mode is enabled on the standard version of Windows Server 2003 with SP1 and Windows XP with SP2, the physical address space is limited to 4 GB. Limiting the physical address space to 4 GB helps prevent PAE mode from having driver compatibility issues.

Only specific hardware supports PAE X86, so this feature is not enabled when the operating system is originally installed. For more information about which hardware supports PAE X86, you can query for hardware compatibility information about products in the Windows Server 2003 family by clicking the appropriate link in the support resource. For more information about how to enable PAE X86, see Enable Physical Address Extensions (PAE).

Solve:

Disabling PAE mode methods

Right-click on the desktop "My Computer" property, select "Advanced", then click "Start and Restore" under "settings", and then click the "Edit" button in the box, you will open the Boot.ini file,

Then this row of the file "multi (0) disk (0) rdisk (0) partition (1)" \windows= "Microsoft WINDOWS XP Professional"/noexecute=optin/ Fastdetect "/noexecute=optin changed to/execute Save the file, and then restart the computer.

Original: http://blog.chinaunix.net/u/11287/showart_124525.html