Laptop has become slow - Dell XPS 15

[rvibin]

Laptop config: i5@ 1.40Ghz | 6GB RAM | GeForce 525M

My DELL XPS 15(l502x) laptop has become slow while browsing and watching movies. I did a reset but the slowness still exists. I then ran hardware diagnostic test and got an error code that stated the hard drive is faulty. I got no other error in that test. Replaced the hard drive with a new one but the problem still exists. My battery stopped working few years back.

I have run the test and the link is give below.
http://www.userbenchmark.com/userrun/8681699

Thanks in advance.

 

[rgd1101]

replace the hdd with a ssd
get more ram
http://www.crucial.com/usa/en/compatible-upgrade-for/Dell/xps-l502x

 

[rvibin]

replace the hdd with a ssd

I couldn't afford to replace it now. Moreover, the laptop is giving me problem only since few months.

 

[rgd1101]

check cpu/gpu temp?