Computer slow to load programs, internet doesn't work.

So my sister came to me the other day as her computer stopped connecting to the internet, and has been apparently getting very slow over the course of a week.


On the internet side of things, we used wired. I tested the ethernet cable she was using on my PC and I could connect fine, but with hers there's no connection at all, but the ethernet port still lights up with the cable in.


The computer seems fine booting up to desktop speed-wise, but loading anything else if tediously slow, even clicking the volume button on the taskbar takes about 5 seconds before the volume slider shows up. And her games have stopped running (and not particulary intensive games either).


At one point I removed the ethernet cable while the PC was on, and that caused it to bluescreen for some reason, looking at some of her PC's logs it's been crashing a few times over the past month or so.


Not sure what to make of this, a friend thinks the ethernet port on the motherboard is done, I don't mind getting a PCI ethernet card.


But as for the slowness, I have scanned her computer for viruses and malware (with ESET Smart Security and Malwarebytes respectively) and removed a lot of unnecessary files with CCleaner, but it made no difference, so I'm at a loss.


Here's what Speccy says is in her system. :

Summary
Operating System
Windows 7 Ultimate 64-bit SP1
CPU
Intel Pentium G3420 @ 3.20GHz 27 °C
Haswell 22nm Technology
RAM
8.00GB Dual-Channel DDR3 @ 798MHz (9-9-9-24)
Motherboard
ASUSTeK COMPUTER INC. H81-PLUS (SOCKET 1150) 28 °C
Graphics
32W_LCD_TV (1360x768@60Hz)
1024MB ATI AMD Radeon HD 7700 Series (ASUStek Computer Inc) 25 °C
Storage
1863GB TOSHIBA DT01ACA200 ATA Device (SATA ) 25 °C
14GB Generic USB SD Reader USB Device (USB )
Optical Drives
PIONEER DVD-RW DVR-221L ATA Device
Audio
AMD High Definition Audio Device
Operating System
Windows 7 Ultimate 64-bit SP1

Oh right, I forgot to address that, there's nothing, the CPU usage and ram usage in task manager are very low, nothing appears to be using an above-normal amount of resources, yet everything is still horrendously slow.

Run a full disk check does the port on the router show a connection try another port. From CMD prompt type ipconfig /all post results

Hi

couple of things, could take a while

from an elevated command mode run

sfc /scannow

chkdsk /r

KB947821, (use the correct version)
if its not any better run the tool from here post results, ignore the title

Blue Screen of Death (BSOD) Posting Instructions


Roy

It can be a disk fault and some files got corrupted as the Ethernet driver.
Open device manager. Is there any yellow alert?
Do a check disk.
Open a CMD window as administrator and type:
chkdsk /f
It will say the drive is in use and if you want to schedule to next boot = yes
reboot
Pay attention on the results, specially bad clusters, bad blocks, bad sectors etc.

Back to windows, do a System File Check
Open a CMD window as administrator and type:
sfc /scannow

As Roy suggested, download and run KB947821