CPU 100 % but no Malware and HijackThis Clean

Your English is fine - better than some who have English as their primary language! But we still have a couple unanswered questions! You said your computer settles down after a bit and works fine.

What do you do to make the problem return?
Does it return every time?

Unfortunately, I don't have much more to offer you. If that PC were on my bench, I would look for ways to free up disk space on both C: and D: drives, and budget for another 512Mb of RAM.

You might want to look in Control Panel Add and Remove Software to see if there is anything you can uninstall. I would also free up some space on your D: drive by deleting some of the files on there. Then perhaps you can move your Page File from C: to D: to free up more space. Although D: is not your boot drive, if some of your applications are trying to write temporary files to D: (and many programs do that when they start up), with D: only having 2Gb free, that may affect performance. And again, you need to make sure Device Manager has no errors and the other suggestions I made.

I also agree 100% with Simon over at MR - you are asking for repeated trouble if you are sharing music and video over P2P sites and strongly recommend you avoid them. You should also heed his advice about scanning for malware, either using the tools he recommends, or you may want to read my canned text on Cleaning Out Malware. Use it if you don't already have a complete security suite and disk cleaning utilities to rid your system of malware and clutter. You can also use it as a guide to build your own security suite, and to help you develop a "Practicing Safe Computing" self-discipline.

Hi Digerati, Sorry for my late reply. Yes, the problem is return all the time. For example, I was doing a research of a Key in Regedit and the application Regdit ( in Task Manager ) went to 100 %. Other example, I tried to open a picture, and the application explorer.exe went to 100 %. At each time when I am doing something in my PC, it's going up to 100 % for a couple of minutes, so impossible to work ,and then going down. Until I am starting a new application, so I can't use my PC. Apparently it's not a malware so I start to have the feeling that it's gonna be hard to find the reason of my problem, I am trying for more than 1 month now, and I start thinking to format my pc…even if don't want to do that. Question, what did you mean with this sentence : "And again, you need to make sure Device Manager has no errors and the other suggestions I made", could you let me know how can I check that? Thanks again for your help, patience and reply. Nico

You definitely need to avoid reformatting as that is ALWAYS a last ditch effort. When you format your boot drive, you lose:

• All hardware drivers, including:
  • Drivers specific to XP SP2 (or Vista),
  • Drivers specific to your motherboard, such as those needed for on-board graphics, sound, networking, USB I/O, SATA/SCSI controllers, etc.
• Data files - including,
  • Documents, spreadsheets, databases, etc.,
  • Photos, music/audio and video,
  • Email (if using Outlook Express, Outlook or so other "client" (PC) based email program), as well as any saved contacts, appointments, and notes,
  • Favorites/Bookmarks
  • Downloaded programs and updates to them, including all your required security applications,
  • Custom configurations, for Windows and all other programs,

and worst of all,

• Security patches and updates end up being months, or even years behind!

So certainly, before starting, you must:

• Ensure you have backed up all critical data and files,
• Have all original installation disks and CD/license keys on hand for Windows as well as any other applications you have installed by CD or DVD,
• Have copies of all hardware drivers on CD, either original maker's driver disks, or better yet, by downloading (the latest version) from maker's download pages and burn them to CD, including drivers for,
  • The motherboard devices (including those for integrated devices)
  • Graphics card (if not integrated)
  • Sound card (if not integrated) (technically, sound is not needed, or at least, can wait),
• SP2 (if not on install disk) - for the cost of shipping and handling (about $3.50 in the US), you can order Windows XP SP2 on CD or download the free Windows XP SP2 Network Installation Package (be sure to install SP2 immediately after XP, before anything else.
• Current copy of your anti-virus program (I would also recommend replacing Windows Firewall with a full two-firewall at this time).

At the very least, you should attempt to repair your installation of XP before attempting to format and reinstall. See Michael Stevens XP Repair Install for complete instructions and necessary precautions.
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For sure, before reformatting, uninstall some of your unused programs and delete some of your unneeded files from both drives to free up some disk space first.

Question, what did you mean with this sentence : "And again, you need to make sure Device Manager has no errors and the other suggestions I made", could you let me know how can I check that?

Look in Device Manager for errors. Right click on My Computer > Properties > Hardware Device Manager. Errors are indicated by yellow and red warning icons.

A trusted colleague suggested you run a PCPitstop Full Test and post the TechExpress link back here. I must admit, I am not very familiar with PCPitstop - I tried it several years ago but was not impressed - I can't recall my exact displeasure, but at the time, there were a lot of sites making all sorts of promises about improving performance, then promptly broke your machine. Popups were rampant then, and an immediate turn off for me too. I just tried PCPitstop on my system and it seems much has improved since then. I am pleased that running scans is free, and without constant badgering to purchase something. I am happy to report my system is running fine, too! Hopefully, someone with more experience analyzing PCPitstop logs will stop by and and give you their input.

I mentioned earlier using Process Explorer or What's Running to determine what is running on your system. You may prefer another recommended program, CodeStuff Starters. It allows you to save a report of what's running from boot, which you can post here too.

Perhaps the logs will shed some light on the problem.

Thanks Digerati for your reply. No errors in the device manager. I am gonna try PCPitstop, for your info I am not here the next 3 days so no internet access, I will reply on sunday. Thanks again for your patience. Cheers Nico

Hi Digeratti,

Please find below the report from Pistop as requested :
http://www.pcpitstop.com/techexpress.asp?id=4YYRSW44MHGS18DG

I am gonna try Cod Stuff STarters as well and post you the report.

Thanks in advance for your help.
Nico

Hey Nico, I have looked over your PCPitStop log and other than seeing a lot of stuff, I don't see any thing bad - but then again, as I said, I am not very familiar with PCPitStop. I do see where it recommends you defrag your hard drive. A fragmented hard drive with low free disk space, and a small amount of RAM will certainly tax your system as it shuffles data around. As mentioned earlier, I recommend you run CCleaner before defragging, and then defrag in Safe Mode for a more efficient defragging.