Upgrade Leading to Black Screen & Constant Slow Performance

[Fyfey96]

Hey,
I got my Raspberry Pi yesterday and its really cool. but I was watching a video of a tutorial and the guy who is showing the stuff his pi just seems do be doing things perfectly straight away but on mines its really laggy and have to wait sometimes just to write in a textbox! I decided I would do the

Code: Select all

apt-get upgrade

and it downloaded it was quite a lot of things, but now during the install the screen has just went black! I don't know what to do. should I unplug and re-boot I don't wanna corrupt update?
Any help soon please for both problems

Thanks

[Fyfey96]

Update: I have fixed the upgrade and got the update but still performance is poor