When MT4 shows as Not Responding (a platform freeze), this typically is caused by either a lack of machine resources, or when the client terminal is overloaded due to processing more than it is designed to handle.
For MT4 specifically, this can be triggered for multiple reasons such as:
Too many indicators or EA's causing the platform to become overloaded
A high quantity of price updates, such as during volatile market times such as news releases. This will further exacerbate any issues caused by indicators and EA's.
Running the client terminal on a machine without adequate resources to handle the processing and memory requirements
For us to try and understand this issue further, it would be helpful for us to take a copy of your platform logs, which are found in these folders through the client terminal:
File > Open Data Folder > logs
If no indicators or EAs are running on the platform, then it is more likely that it is a resource issue on the machine - which may be either due to other processes running on the machine consuming the available resources, or those resources being too low to handle the needs of MT4.