If you get a little balloon in the bottom right-hand corner announcing that your virtual memory is low and that Windows is adjusting it, and this happens just once, don't worry. As the message said, Windows found a problem and fixed it. But if it happens repeatedly, it could be that your settings don't allow Windows to make the necessary adjustment. First, make sure your drive isn't overly full. In Windows Explorer, right-click the drive icon and choose Properties. If the amount of free space is under about 10 percent, you'll need to free up some space. You can use the Disk Cleanup button right next to the free space indicator, or manually move some files to off-line storage, or uninstall unnecessary applications, whatever it takes to get more free space.
If low drive space isn't the problem, the virtual-memory settings may be wrong. Right-click My Computer and choose Properties. Click the Advanced tab. Click the Settings button in the Performance panel. Click the Advanced tab in the Performance dialog. Click the Change button in the Virtual memory panel. Whew! This setting is buried quite thoroughly! Look for the System managed size option, select it if it isn't already selected, and then click OK, OK, OK. That should end the warnings.