Can I be threatened legally if I join former employee of the previous company if my contract does not specify radius on joining?

Non-competition clauses generally apply if the employee leaves the company of his/her own volition. If you are laid off because your employer is insolvent, the restriction may not apply to you. I recently won a judgment in the Circuit Court for Baltimore County declaring a non-competition clause unenforceable -- but each case is unique. Bring your employment contract to an attorney before you take any action