The TCase is a number established by Intel® as a point of reference in order to understand what could be expected as per normal processor temperature.
Anything from the Tcase and below will be the expected temperature of the processor in normal use, anything that doesn't stress out the processor (watching movies, burning CDs, browsing the internet, creating documents, etc.) When the processor is stressed out meaning that you are running heavy processor applications that take control of the CPU or uses it at 100% the temperature will go beyond the Tcase. It can perfectly reach 80 to 85 degrees and the processor will still be OK. The cooling fan is in charge to keep that temperature there.
If the processor temperature reaches 100 degrees or more it will send a signal to the motherboard to shut down to prevent mayor damages and most likely it will not be possible to turn the computer back in until it cools down.
The normal processor temperature will depend on the chassis type, the hardware involved and the location of the computer, and it usually is lower than the Tcase. According to the system behavior, 76°C while placing load on the processor is normal.
The TCase value for your Intel(R) Core(tm) i7 processor I7- 3770K is 67.4°C: http://ark.intel.com/products/65523/Intel-Core-i7-3770K-Processor-8M-Cache-up-to-3_90-GHz?q=-3770K
For troubleshooting over heating conflicts you can proceed with the following:
Update the BIOS to the latest version in order to have the proper microcode of your processor, which will help on the proper recognition.
Check the processor and system fan(s) to see if any have been disconnected or are blocked by a foreign object.
Make sure that there is proper airflow in and around your system
Your system should be kept in a room that has adequate cooling; the room's ambient temperature should be below 90 °F (32 °C).
Check that the processor's heat sink has been installed properly.
Make sure your system's I/O (disk, floppy, CD-ROM, etc.) cables aren't restricting airflow in the system.
You can also run the Intel® Processor Identification Utility to check how the processor is being recognized: http://downloadcenter.intel.com/Detail_Desc.aspx?DwnldID=7838
Also, feel free verifying your processor’s functionality: http://www.intel.com/support/processors/sb/CS-031726.htm
If this does not solve your issue feel free contacting your local support group during business hours: http://www.intel.com/p/en_US/support/contactsupport