Did he tried a system restore?
How to do it:
1) Reboot the computer and start windows in safe mode (tap F8 just before the boot screen appears and select Safe Mode)
2) Launch System restore. (Start - Programs - Accessories - System Tools - System Restore
3) Select "Restore my computer to an earlier time", "Next"
4) Select one of the bold dates from the calendar before his internet didn't worked any more (example: if his internet didn't worked starting 2 September, select the first bold date which is before 2 Sept., like 31 august).
5) Select near the calendar one of the restore points from that day (if there are more than one) and press Next
Your system will be restored to that date. This means all programs installed after that date will be uninstalled, all programs uninstalled after that date will be reinstalled. It will simply redo what the user did. Note: This won't delete new files created after the selected date or create files deleted in this period of time.