Laptop keeps crashing. Windows 7

Help Please!!!

Thank you all in advance

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, 64 bit
Processor: Intel(R) Core(TM) i7 CPU Q 740 @ 1.73GHz, Intel64 Family 6 Model 30 Stepping 5
Processor Count: 8
RAM: 4076 Mb
Graphics Card: NVIDIA GeForce GT 425M, 1024 Mb
Hard Drives: C: Total - 600212 MB, Free - 489996 MB;
Motherboard: Sony Corporation, VAIO
Antivirus: avast! Antivirus, Updated and Enabled