Chikkupaul, when did you buy this unit? Best bet from my side would be that it is win ce, but which version can be (very) roughly calculated based on your purchase date. For example, my GPS is Teletype Worldnav which I bought in US in 2007 and it came loaded with win ce 4.2. I believe post 2007 devices started coming with ce 5.0. Once I came to India, I removed the teletype software in it and put in NDrive. Best way to determine your OS version wud be to do wats given in this thread --> How to unlock any gps wce 4.2/5/6 Try that and let me know if it works, if not I will help you step by step in getting something installed.