laptop overall lag

[Fluu]

i have a Dell Inspiron N5110 that im been using since 2012,everything works fine until this year,my brother already format this laptop and replace the current hard drive with a new one.

but its still laggy.

and somehow yesterday my laptop works fine,
games like dota 2,team fortress 2 and even borderlands 2 works fine on med/high setting with a decent fps.

and today when i turned on my laptop,its laggy again. jeez.
can someone help me,pleaseee

i already tried:
defragment my hard drive
run a disk check

sorry for my bad english,english is not my native language.

My pc/laptop spec:
Processor: Intel (R) Core (TM) i5-2450m CPU @ 2.30ghz
RAM: 8 GB
OS: Windows 7 64 Bit Home Premium
Graphic Card: Intel HD Graphics 3000/Geforce GT525M

 

[Fluu]

nvm, i replaced my old charger with a new one aaand its fixed, lmao