something running in the background

ScumLord

Friends PC is slowing down there's spikes of full CPU usage and I can't figure out what it is. It looks like a virus but AVG if fully updated and the PCs been fully scanned a few times. It is set for automatic updates from windows, there's very little on he PC to cause problems.


The PC is running WinXP Pro SP3 and is mostly used for CAD work.

I've looked under processes and it's only system idle process that is causing the 100% usage spike.

When I get the chance I'm going to turn off services until it stops but are there any shortcuts to finding out what the problem is?

PaddyTheNth

The system idle process is effectively a measure of how much of your CPU's potential is not being utilised by what you're running.

Download Process Explorer and see if that helps to identify what is actually causing the spike in CPU usage. If you can't work it out try showing the CPU time column and see what the total usage figures for each process look like after a couple of hours.

Capt'n Midnight

also check out the hard drive as this will slow down intermittantly on bad sectors

run hdtune a few times , you should get a spikey curve with a few blips
if there are many dips then something is hogging the hard drive, you can also do a surface scan too while you are at it

windows also has a performance monitor built in where you can measure a Brazillian things, but procexp is much easier

ScumLord

Blibs like these?

Capt'n Midnight

yes

but it only applies if the pc is idle
if you have av scans or windows updates in the background they might be using the drive too

watty

Or oddly CD or other Autorun.

I've always had all autoruns off on everything since forever as part of my paranoid "spot attack vectors early" schema.

One particular MS patch turned it on. I was going scatty trying to figure why my laptop was suddenly accessing the HDD about once a second or so.

ScumLord

Capt'n Midnight wrote: »

yes

but it only applies if the pc is idle
if you have av scans or windows updates in the background they might be using the drive too

The PC was left on overnight, it's scan and updates are set for during lunch time.

It's weird because when ever I sit in front of it, it hangs for a few seconds but then it's fine and I can't see anything wrong with it. It hangs constantly for him.

Capt'n Midnight

run diagnostics on the drive perhaps

ScumLord

I ran a scan for damaged sectors using HD tune but it said the disk was fine.

Capt'n Midnight

at this stage perhaps run hijack this and post in the virus removal fromun http://www.boards.ie/vbulletin/forumdisplay.php?f=1009

watty

or run www.silentrunners.org
Some expertise needed to interpret what it is telling you. However it's a technique that finds malware that AV vendors don't know about. Booting in safe mode and removing evil entries usually cleanses.

Note that some DELL supplied keyboard drivers appear flagged, but if you remove them you have no keyboard They arn't malware.