My school uses these dell optiplexes with core duo and 2 gb ram. They are about 8-10 years old. They play minecraft like a slideshow and lag on meatspin...We used to have these vista laptops that were surprisingly decent. Now we have Windows 8 hp laptops that actually worse .
There might be a notification in the bottom right hand corner of the screen. Click on it. If not... buy a disk. Did you already buy the disk and are having problems?
I would also look at HTC. I have the One M8 and it is fantastic. LG is good. Moto X is good. Nexus is good. iPhones suck. Windows phones are ok. I would get the next Nexus phone for your needs.