Yes sure.You can use two platforms at same time on same computer.You can sign in to both MT4 and MT5 platforms at same time on one computer.It will help you to make more profits by using two platforms at a time.So,just deposit your money and start trading.
You can have two trading platforms (MT4 & MT5) on the same computer but cannot run both simultaneously using the same login id. Two instances of the same platform can even be run but with different login id and password. This is based on my experience. Also, try to install the platform on a different drive. You can't run demos and real accounts on the same platform even at different times. Another important thing I want to inform you is that only one of them will function and the other will hang your system when you log out of one account and try to log in to another. and I recently installed MT4 and MT5 on my computer that wants to access my same account from two different platforms, unfortunately you cannot log in to MT4 Account using the MT5 platform. But if you install two MT4 Trading Platforms on the same computer, I'm sure you can access different or the same MT4 Account.