Computers can and will fail for a billion different reasons. First thing to do if it will turn on but not finish loading windows is to power the machine down. Now that the machine is off you need to turn the power back on. As the system begins to start tap the F8 button. You will see a black screen with a multi part menu displayed. Select SAFE MODE. AFTER SELECTING SAFE MODE YOUR SYSTEM SHOULD BOOT You will then be asked what user to load.. ADMINISTRATOR is the choice for you. After this the system will load the safe mode windows. Follow these steps exactly. Click START, ALL PROGRAMS , ACCESSORIES , SYSTEM TOOLS SYSTEM RESTORE At this point you will select RESTORE MY SYSTEM TO AN EARLIER DATE. Now what you want to do is select a date from the calendar from the left that is before you started to have any problems. ((NOTE)) I personally always grab a date 3 days before I had a problem JUST IN CASE After you do this and select restore your system will reboot. ((this may take upto a half hour)) let windows load you should be good to go