How to proceed in these kind of issues :
Step 1 : Check the disk space where the data files reside. If you are running out of disk space. There is the problem.You will have to either increase the disk space in that drive or you will have to create a secondary file into a drive with sufficient space available while limiting growth in mdf.Adding an ndf file and disabling autogrowth on the primary mdf will solve the problem for that moment.
If you see sufficient disk space then it it something to do with the database settings.
Step 2 : Right click the database to check the properties.Go to files page :
Check if Autogrowth is enabled or not. If autogrowth is not enabled and the datafile has reached the limit, you will receive primary file group full error.
- Tick the checkbox to enable AutoGrowth
If you find it set to 'Limited',then either increase the limit you can afford the db to grow or make it unlimited.
Learn more about Autogrowth click here
Deleting data from tables can be done once the main problem is fixed. Also data deletion is not an option when you are taking care of Production systems. Deleting data fill not shrink your data file itself, you will need to re-index and shrink it manually if needed.