Error Code 0×490 indicates bad boot information, which does not let you access Windows 7. In this situation Boot manager is unable to find OS Loader and is stuck at the startup phase. By default or by command, it runs a repair process, which also subsequently fails.
.NET Framework is used for developing web-based and windows-based applications.Often times,you may experience Error Code 0x800F0906 While Enabling .NET Framework 3.5
At times, your PC shutdowns automatically while you are working. In fact something in the boot process is crashing the PC. Formerly Windows reacts to the crash by rebooting. Follow this Video tutorial to fix the issue