I'm using Windows Vista Home Premium on a 64 bit HP Laptop with 4GB RAM. I'm networked with several other computers. When I try to get to the desktop on my Windows 7 machine the Network displays the Windows 7 desktop for an instant and then reverts to the Windows Vista desktop.

The procedure I'm using:
I double-click the Network icon on the Vista desktop. In the window that opens I click on my windows 7 icon, enter the appropriate login and password, and then click the desktop icon to open the Windows 7 desktop in order to transfer files, etc. The Windows 7 desktop opens for an instant and then all the open windows disappear and the Vista desktop reopens. If I use the same process to open the Windows 8 desktop it functions normally and I can see and transfer files.

This problem just started occurring. Any ideas on what's causing the problem and how to fix it?