Recently my customer bought 4 new PCs. These PCs will hang after these sequences of events.
1. Run my exe
2. Exit from my program
3. Any attempt to run anything will hang the system.

I tried running it from both the network and the local PCs. Same problem. However all the existing PCs don't give any problem. When it hangs, a black window will appear and I can only cold-boot to restart the system. Please note that other existing sets of PCs are running well and they are running the same program from the network drive.