BleepingComputer.com: PC slowing down

Hi,

My computers on a bit of a mad one, its fine most of the time but as it gets later in the day it goes off on one.

Take today for example, came in at about 5 used the pc lovely, gets to about 8pm and its slowing down drastically and I dont know whats causing it. if I open a web browser or jus a new tab in the browser my CPU will get to 100% load which isnt natural for a core 2 quad @2.50Ghz im sure.

InitiallyI though perhaps viruses so ive booted in safe mode before running a search with Spybot S&D followed by another scan with MalwareBytes, neither of these reported anything and nor has my real time scanner Avast!

Gone back to a previous restore point which hasnt fixed problems either so I though maybe hardware related, as its slowing down overtime I though maybe overheating was the cause. However looking at my temperatures they are normal and all at roughly the same early in the day as they are at night.

Because of this im at a loss
Sorry if this is in the wrong place but I didnt know where to put it, seems im using Windows Vista it seemed a logical place to put it.

Anyhelp that could be provided I would be very grateful for, any further details needed please just ask.

We are going to disable startup programs to determine if one or any of them are causing this slowness.

To perform a diagnostic startup, follow these steps:

1. Click Start, click Run, type msconfig, and then click OK.
2. On the General tab, click Diagnostic Startup, and then click OK.
3. Restart your computer.

Take note whether or not you experience any degradation of performance over time like before. Now, go to the Startup tab of msconfig and check the box next to one startup program > Apply > OK > reboot

You will have to do this one program at a time (enable, reboot) until you find the one(s) that is causing the slowness. This could take a while, as you said it becomes slow over the matter of a few hours. This is harder to troubleshoot, as opposed to just slow boots (pretty quick to test).

Have you checked the Task Manager to see which process is using all that CPU when it spikes like that?

Thanks for your help, im currently testing enabling one at a time when I get some time, ive got about 10 different startup items so its going to take a while seems its a few ours in before slowdown occurs.

What I do notice though in task manager is that when the slowdown occurs and I open internet explorer the memory usage goes up to about 25,000K jsut for iexplorer and with firefox it jsut about reach 60,000K, surely thats not right

The thing about Firefox is this: the longer you use it, the more memory it uses. It's memory usage doesn't fluctuate (go back down) with the level of usage or number of tabs/windows open...it only goes up. Eventually, if you browse long enough, Firefox's memory usage goes above 200,000 Kb (I've done it). At that point, things start to go a little wacky and some things don't work right (emails won't send, pages won't load, etc.). The only solution is to close all Firefox windows, then restart Firefox. This "resets" the memory usage.

See here: http://support.mozilla.com/en-US/kb/High+memory+usage

This may be contributing to your slowness acquired over time.

But yeah, see if the diagnostic startups can find a particular program that is causing this problem. I typically leave my computer on for days at a time without rebooting...only putting it to "sleep" when I don't use it. So, having the computer on itself for that period of time shouldn't be causing the gradual slowing down....it has to be the programs you are running (possibly internet browsers).

Do you leave a browser window open all the time?

I rarely use firefox but I suppose I leave internet explorer open often, if im on the computer im usually browsing one page or another.

Only things ive changed recently are going back to vista 32x from the Windows 7 x64 Beta,
Added another HDD
And started using Dual monitor support

Would any of those have any real baring on it, I doubt it but things often act strangely.