All versions of Windows from Windows 95 and later use virtual memory. Virtual memory is a complex and sophisticated system, it is NOT the pagefile. This system is always in use and cannot be disabled.
From description it looks that all of them do.
You can run a virtual machine under WIN7 and run whatever OS you might need to satisfy Borderlands. Start-->All Programs-->Windows Virtual PC-->Windows Virtual PC or Windows XP Mode. I have several versions of Linux running as virtual machines on my install in addition to WINXP.
Windows will automatically set your virtual memory size. It all depends on how much free space there is on your hard drive. Your physical memory is your RAM. 1GB of RAM is the same as 1024MB.
In all modern versions of Windows these settings are in the registry, not in configuration files. An interface is provided for the more common settings but should only be changed by someone who understands the implications. Anyone who does not know how to acces these settings clearly should not be touching them.
Page file in windows is identical to swap memory in unix based systems. Microsoft gives a different name to all the terms and hence the page file.
Physical memory, as with all computer resources, is managed by the system. Applications access virtual memory exclusively, no exceptions, ever. Physical memory (RAM), the pagefile, and many other files on the hardisk make up the virtual memory system. This system has been extensively researched and tested and it usually performs very well. Virtual memory is VERY complex, and the designers understand it better than you do.
Virtual memory is a way of allocated extra space from your hard drive as RAM space. For instance, if you are running a program which is memory intensive such as Photoshop and you don't have enough RAM to handle all the temporary memory requirements, but you have a few extra gigs of space on your hard drive, you can set your Virtual Memory to 2 or 3 GB's to help balance the load.
All versions of Excel should work with all versions of Windows.
Only PDMS 12. can be installed in windows 7 with, proper patches , all previous pdms versions can not be installed on windows 7 or Vista. However you can try with creating virtual machin with xp.
Spore works for all windows versions.
Windows handles the virtual memory and there really isn't a way to clear it. Virtual memory is stored on the hard drive. It basically uses your hard drive as more RAM. You can't clear virtual memory any more than you can clear your RAM. It is possible to set the size of the virtual memory that Windows can create. This is done (if you have XP) through the control panel -> System -> Advanced -> Performance Settings -> Advanced -> Virtual Memory Change (other OSs will have it in roughly the same place). As you can see it isn't easy to find, because changing it can result in very bad things. If you make it too small, you system may crash when it runs out of physical RAM. Too large and you waste hard drive space. It's usually 1.5G, or smaller for older systems. Personally, I would just leave it alone. Windows only uses virtual memory as a last resort, and usually picks a reasonable size.
Virtual memory management assist in the process of multitasking by providing extra memory when a computer has used up all its RAM. Virtual memory is however slower than RAM.