ArcGIS 10.1 Crashes When Open map

I'm very concerned I'm taking a class, and I cannot get ArcGIS 10.1 (ArcView Single User Advanced) to work properly. I upgraded from ArcGIS 10.0 (which worked fine on this computer!) When I simply say file - open, and try to open an old map created in ArcGIS 10.0 (ArcInfo student version), ArcGIS 10.1 crashes! Eventually, sometimes I can get a folder to open. Once a particular folder is opened?? I can then load the maps in that folder. I'm not sure what the difference is. It may have to do with the internet connection. I was able to open these old maps when I was disconnected from the internet. I am now connected to the internet 100mb/s and it crashes when I open maps that haven't yet been opened in ArcGIS 10.1. I can open maps from ArCGIS 10.0, that I was able to open while I was disconnected from the internet.

I uninstalled Kasperksy Pure 2.0 Internet Security. This hasn't solved the problem. I now have Microsoft Security Essentials as virus ware. with Windows Firewall.

I'm afraid I may have to drop this class which requires 10.1 as I cannot open my old maps which I need to work on for my thesis work.

Please Help! I have HP Elitebook 8540p, with XP Professional 32 bit mode, i7 old processor, 1 gb discrete graphics, nvida.

I noted in add/remove programs Python 2.6 is installed, shouldn't it be 2.7?