right click your taskbar and untick "lock the taskbar"
left click on an empty space on the taskbar and move your mouse to the bottom of the screen.adjust the size of it by hovering the mouse over the top edge of the taskbar untill you see two little arrows and just drag up or down.
right click again and lock it.
as for your start up pop up.whats the program asking to register?
try start/run type msconfig click the start up tab and untick everything except your av and firewall.if you know what the program is though there may be a run at start up option you can disable within it.