A cell phone, no matter which model, is not a replacement for a computer. Get a cheap netbook or laptop computer instead. There is no easy way (if it all) to do what you want to accomplish with your phone.
I have an HTC Sensation XE. This is a very powerful phone that I would like to use as a computer.
I purchased the USB2HDMI adapter that allows me to connect the phone to my 42 inch TV to use as a monitor. In theory this is sufficient to do what I want, but:
The HDMI cable in addition to the adapter and the power cable is too much weight for the mini USB socket on the phone. Its fine if the phone is not being moved but the stain should the phone be moved is excessive and if that port breaks I cannot recharge the battery.
What I would like to do is to connect the phone additionally to some kind of wireless keyboard / pointing device. This would allow me to leave the phone cabled in and then use it as a PC without moving it.
I have tried the bluetooth keyboard we purchased for my daughter's ipad. This works fine - but there is no way of negotiating the menus - opening apps or navigating around the screen.