Welcome to SevenForums.
Is the firmware of the SSD, up to date?
The antivirus you are currently using is known to cause crashes, consider uninstalling it with the McAfee Removal Tool and replace with Microsoft Security Essentials at least to test. You may install it back if we know it wasn't creating a problem.
Recommended antivirus program for Windows 7 based on stability compared to others:-
Do not start the free trial of Malware Bytes; remember to deselect that option when prompted.
Run a full scan with both (separately) once downloaded, installed and updated.
Run the System File Checker that scans the of all protected Windows 7
system files and replaces incorrect corrupted, changed/modified, or damaged versions with the correct versions if possible:
Run Disk Check on your hard disk for file system errors and bad sectors on it:
Let us know the results.