Hello, I apologize for my terrible English, thank you for reading and help me.

I am using Window Vista, DSL Internet.
My internet for the past week is not good. Throughout the whole day my internet fluctuates, up and down fluctuates speed all day. My DSL download speed always been good, I always get 300KB/sec stable speed, until last week suddenly it start to drop from 300KB/sec down to 6KB/sec, This is a big change, something is definately wrong.

I call my Verizon DSL, they do a line test on their side and they say my Modemn recieve good signal, also the DSL light on my modemn is always solid, so I am sure it recieve good signal.
So if nothing is wrong on their side, maybe it my computer hardware?
I also do a Safe Mode Networking with Verizon, I run my computer in Safe Mode Networking, and the internet speed still drop dramatically starting from 300KB/s down to 6KB/s . Since I am on Safe Mode Networking and this problem still exist, it is definately not any software conflict.
I also scan my computer with numerous of anti-virus from Norton, mcAfee, Kaspersky, Housecall, Esset, including Malwarebyte and lavasoft, and found Nothing!!!!! No virus, no spyware, Nothing!!!

So all that has rules out, now the only option left I can think of is something wrong with my Vista hardware. How can I know if something is wrong with my hardware? Can anyone please hlep me. Something is wrong, I just cannot figure out what it is.
Thank you so much!!

Hi, I'm pretty sure that vista is not the cause of this problem. Try updating the drivers for your modem/ internet drivers. Have you done the basic unplugging of modem and after 10 seconds going back?

I'm unsure of why its running slow.

What internet browser do you use?

There are many tools that can adjust your settings for quicker internet.

There is a high chance that some settings in your browser have gone wrong and that is causing you this slow internet.

FYI, there's no such thing as "Vista hardware"... Vista is the operating system, which is software. So, I think you meant to say "computer hardware".

If you didn't install anything new on your computer and virus checks turn up negative, it's not likely that the problem is with your computer hardware or operating system. Your internal network card would be the first thing to consider if it was a hardware problem, but if it's a relatively new computer then it's built into the motherboard and it's not something modular that can be replaced. In any case, a hardware failure usually means NO function at all, not reduced functionality.

Are you directly wired to the cable modem, or are you using it with wireless? If wireless, does your cable modem have built-in WiFi, or do you use a separate wireless router? Can you get access to another computer to try using your DSL connection and see if the same performance results?

If you had two different anti-virus programs installed, this could cause the problem. But, the Kaspersky Security Scan provided on-line is a one-shot deal. There's nothing that Kaspersky does that would mess up your system--it just looks for potential virus threats.

It's possible that your network connection profile has been damaged/compromised. If you're having issues with pinging connections, perhaps you need to flush your DNS resolver cache. I'd also check your Auto Tuning TCP/IP receive levels.


Just to rule out any contributing issues at the system level, I also suggest you run SFC scannow (start from "Here's How" and proceed).

Thank you, you are so helpful. I will try all your recommendation.
How to know if my network connection profile have been damage? Is there any way I can reset the network profile setting? I have try open firewall advance setting and no error message show.
Currently my computer window firewall is Off, because my Norton firewall is On, so it turn off my window firewall.
Just wondering have you ever try the Kaspersky online scan before? I worried this is why my internet is slow now.

The Kapersky online scan does require installation of their .exe in order to scan, after I have this problem, I have uninstal it from my system. Since Kaspersky is not a Real Time protection though, so I don't think it conflict with Norton.

I use window Vista Home Professional edition in x32, Vistax64 and vistax32 is similar? I can try follow the clear DNS steps ? Since the link you give me is vista64


I success flush the DNS, but no luck, my speed start out from 200KB/sec now down to 16KB/sec





I have try check Auto Tunning TCP, I show the screenshot below:
Does it look OK? Sorry I am not good with computer

My Auto Tuning TCP settings match yours exactly. So, I think you're fine there. The tutorials apply to both 32 and 64 bit systems.

So you're using the Norton Internet Security firewall. Hmmm... Well, just to help narrow down the problem, try seeing if you can rule out Norton. Disable the firewall and anti-virus, then open up your browser and visit only highly trusted websites. See if there's any performance difference.