My computer seems to idle at 25% processor usage. I looked at task manager and it rather helpfully told me it was 'System', so I downloaded Process Explorer and had a look at the threads under system and the culprit was labelled as 'ACPI.sys+0x1af7c', showing a near-constant 25% CPU usage! I've attached what I'm seeing.

The computer I'm using is listed under my Comp. Specs forum info as 'Main Computer MEGA-NUKE'.

I've had this computer for over half a year with no such trouble. The only thing I can think of that I've changed just before I noticed the issue was upgrading my OS to SP1, and downloading a few other important updates. I don't download any updates other than the ones listed as 'important' (exception is the Browser Choice Screen) as I've had bad experiences in the past with it, but I'm hoping Windows is better at handling updates currently.

Thanks in advance to anyone ATTEMPTING to help me.

EDIT: As far as I can tell all my hardware is UPDATED to the latest set of drivers provided by their manufacturers. I've unplugged all non-critical devices (keeping mouse, keyboard and screen).

EDIT2: Ran a full scan with AVG Free to no avail. My chipset drivers are fully updated.

[year+ old attachment deleted by admin]As a starting point I'd suggest running full scans with both your anti virus app AND MalwareBytes.

I'd also suggest checking for a bios update and a more current chipset driver.I suspect chipset driver...Thank you for the quick reply.

Is a BIOS update safe? I've been warned against it.

I've run full scans with AVG Free (sorry, forgot to mention).

I'm afraid to say my chipset driver is fully updated.

I'm performing a full scan on C: my only HDD with fully updated MBAM.I've performed literally dozens of bios updates over the years and never had a problem. Just follow the instructions. The biggest cause of problems is an interruption in the update (power outage, a user stops the update, etc). Can something bad happen? Sure, I suppose so. But I've never had any issues at all.

And it's my guess that if there is a bios update available, it will address your issue.It may be of use to know that I have an Asus P7P55D-E LX motherboard.

I've downloaded the latest BIOS version but I've yet to change anything. According to the website my version number is higher than the version that first supported my CPU, so I'd rather not 'flash' it or whatever UNLESS you feel it may help anyway.

EDIT: Okay, I'll do it as soon as MBAM's finished.First suggestion upon seeing ACPI.SYS: ensure you're using the latest BIOS available for your motherboard. Else, reset current BIOS settings after noting current settings. If you're overclocking, stop.
Scan just finished:

Code: [SELECT]Malwarebytes Anti-Malware 1.60.1.1000
www.malwarebytes.org

Database version: v2012.04.04.06

Windows 7 Service Pack 1 x64 NTFS
Internet Explorer 9.0.8112.16421
Chris :: MEGANUKE [administrator]

04/04/2012 17:05:49
mbam-log-2012-04-04 (17-05-49).txt

Scan type: Full scan
Scan OPTIONS enabled: Memory | Startup | Registry | File System | Heuristics/Extra | Heuristics/Shuriken | PUP | PUM
Scan options disabled: P2P
Objects scanned: 929975
Time elapsed: 1 hour(s), 36 minute(s), 40 second(s)

Memory Processes Detected: 0
(No malicious items detected)

Memory Modules Detected: 0
(No malicious items detected)

Registry Keys Detected: 0
(No malicious items detected)

Registry Values Detected: 0
(No malicious items detected)

Registry Data Items Detected: 0
(No malicious items detected)

Folders Detected: 0
(No malicious items detected)

Files Detected: 3
C:\masm32\topgun.exe (Trojan.Dropper.PGen) -> No action taken.
C:\ASPIRE6530G\Users\Chris\AppData\Roaming\.minecraft\Cart\Cartograph_G_Post_Processor.exe (Trojan.Agent.cn) -> Quarantined and deleted successfully.
C:\ASPIRE6530G\Windows.old\Users\Christopher\Documents\Old Documents (Extract only)\Personal\publish\tarsvx1002.exe (Adware.Onlinegames) -> Quarantined and deleted successfully.

(end)

C:\masm32\topgun.exe I'll vouch for, I removed the other two. I get the impression that this search hasn't turned up any solutions to my problem but at least I'm clean.

I shall now procede to flash the ROM or whatever it's called, and then I'll try default settings (and no, I'm not O.C.ing).After updating the BIOS the problem continues to persist.

I shall now reset the BIOS to default settings.Well, the good news is your computer didn't explode Quote from: Allan on April 04, 2012, 11:57:31 AM

Well, the good news is your computer didn't explode

Let's try a selective startup.

Open msconfig and on the General tab choose "selective startup" (uncheck all three items) and reboot. Does the problem still occur? If not, start adding items back to msconfig one or two at a time, rebooting after each change, until the problem reappears and you'll have identified the offending process. This is clearly a time consuming procedure, but it is the best way to determine if some process loading with the system is the cause of your problem.

After you've isolated the cause, do not use msconfig to permanently disable the process. Instead, if it is a service go to START - RUN and type: services.msc (then press enter) and disable the service OR, if it a program, you can download & run a simple app such as Mike Lin's Startup Control Panel (http://www.mlin.net/StartupCPL.shtml) to enable, disable, or otherwise manage startup programs.

Please look in device manager. Are there any yellow or red symbols?

And one other thing you can try. Please replace the battery on the motherboard.