After reinstalling Win 7, problems with booting, restores on startup

Win 7 Ultimate, Dell n7110

Lately Win became very laggy anpd unresponsive so I reinstalled Windows. It worked fine until few days when the same issues started + problems with booting (very slow, had to use Repair etc). I reinstalled again. I had only few programs on it, just started to fill it up with files and now for the second time after installing drivers it won't boot normally, it performs System Restore and Repair, and when it starts working again, it removes graphic and network drivers and I have to install it again each time this happens. It happens usually after laptop does Win Update.

Issues started a long time ago, can it be faulty HDD? Chkdsk shows a lot of unreadable sectors.
I am thinking about replacing HDD because these problems happen really often even after reinstalling windows.
Is it HDD or any other hardware causing this? :/
I'm struggling with this laptop for a long time now and can't work normally on it, I am worrying each day will it boot or not.

Valentinee said:

Chkdsk shows a lot of unreadable sectors.

It's probably hard drive.
Download HD Tune website and run error scan.
Bad sectors on hard drive can slow your hard disk and you risk losing your data.
Your hard disk might be corrupting really fast based on your information,as it tries to read certain sectors they become unreadable and they get relocated,therefore hard disk becomes slower.

Download HD Tune website and run error scan.

Error scan showed around 22% damaged blocks and around 503+ errors before BSOD shut my laptop down (had only internet and HD Tune running at the time)

Valentinee said:

Download HD Tune website and run error scan.

Error scan showed around 22% damaged blocks and around 503+ errors before BSOD shut my laptop down (had only internet and HD Tune running at the time)

Oh that's pretty bad.Get a new hard drive asap.
Also,back up your data!

I don't have any important data on it since I recently reinstalled windows.
I just wanted for someone to confirm I should replace the HDD.
If new one will solve all of these problems, that's what I will do, thank you for your help!

You're welcome ,
I'm glad I could help.