Laptop problems, Slow and malfunctioning

Hello,
I've been having some problems with my Asus laptop lately, I'll try to explain the problems as detailed as possible:

Specs:
Asus n71jq
Windows® 7 Home Premium
Intel Core i7 720QM
1,6GHz
Radeon Mobility HD5730
4GB RAM
DDR3 (SODIMM)
(Not sure if there's anything else I should list here)

So here are the problems:
-It takes forever to start up and get ready for use (Literally 5 minutes)
-It shuts down every now and then (Probably because of the heat?)
-At certain websites it freezes up for approx. 1-2min (Wallbase for example, and by loading this forum)
-I can barely run games on lowest settings on fullscreen cause of the lag it produces, however I should be able to play them without problems.
-Sometimes it randomly stops random USB ports from working (While having my tablet connected to it)

I think it has to do with my hard disk, although I'm not sure of it.

A few months ago I sent it to Asus for repairs, all they did was clean the fan and they installed a new windows on it. Which didn't solve anything and took them a month (Which is the reason I'd rather not do that again)

Any help would be appreciated.

Regards,
Gold Streams

EDIT:
ChkDsk didn't return anything, I've managed to find this error though: http://puu.sh/2vFyc However I'm not sure what to do with this or whether it's related