CPU running at 100%

Can anyone tell me why my CPU constantly runs ay 100%

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and select "Task Manager" --> "Processes" Tag
Check which process use 99 "CPU". If "iexplorer", highlight it and press "End process"

LenAbAuthor Commented:
I've checked Task Manager.  The process that shows most usage is iosdt.exe (78 - 85)

  It's Trojan Horse (virus).
Open Control Panel > Folder Options
Click the View tab.
Under Hidden Files & Folders click "Show Hidden Files and Folders"
Next uncheck "Hide protected operating system files"
Reboot in Safe Mode (in XP press F8 before windows begins loading)
Open C:\WINDOWS\system32
Delete the Folders & files with iosdt in the name (there should be 1 folder, iosdt, containing all the corrupt files) you may want to do a search for iosdt to make sure everything is removed.
Empty the Recycle Bin.
Reboot in Normal Mode.
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Start -> run -> regedit
and then:
go to HKEY_LOCAL_MACHINE - Software - Distributed Computing Technologies Inc.  and it will be something like C:\ Windows\ System32\iosdt\iosdt.exe
1. turn off system restore - right click on my computer->properties->system restore and turn if off.

2. search your entire system for iosdt - you should find an iosdt folder in the system32 folder and a couple .pf files in your winnt\Prefetch folder.  DELETE all of these entries.

3. start regedit (advanced user feature be very careful you can corrupt your entire system installation by making mistakes in the regeditor) - Once in regedit do a complete registry scan for iosdt.
(a) You should find an entry in the services section of the hklm - system - controlset# - services section for dcnet and under that key will be the entry to launch the iosdt.exe client application.  DELETE the entire DCNET key if iosdt.exe is the only application launhed.  If these are other applications then just delete the iosdt.exe entry from the registry.  You may find this in more then one registry location.  Delete all of them.
(b) You should also find a key for Distributed Network Technologies in you hklm - software section.  Delete the ENTIRE key if iosdt.exe is the only application installed.  Otherwise, just delete the iosdt.exe key entry.
Basically on some systems the DCNET service might be running logitamate applications and I don't want to have you arbitrarily delete the entire keys.  However, in some cases this might be okay if you have the ability to know what DCNET applications your are running and can re-install them.  Then completelt blowing anything related to DCNET out of the registry would probably not be a bad idea.
Close the regedit app.

4. reboot your machine

5. turn system restore back on


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You could also go to the link below.

It's a good free online virus scan that might help.
Or scan with stinger:

run all these :

     Spybot :        http://www.download.com/3000-8022-10122137.html
     adaware :      http://www.lavasoftusa.com/
     STINGER  :   http://vil.nai.com/vil/stinger/   
http://housecall.trendmicro.com/                                           online scan for trojans
http://www.spychecker.com/program/coolwebshredder.html            CWshredder
http://www.spychecker.com/program/hijackthis.html                           download
http://www.hijackthis.de/index.php?langselect=english                            check the log
First of all get a gud Antivirus software like Norton or McAfee... and ensure to keep ur virus definitions  upto date. Along with  the Antivirus, get one Adware/Spyware remover like ADAWARE from Lavasoft. Third thing u need is a personal firewall like Norton Internet Security or Zone Alarm Personal Firewall or use WinXP SP2 which has a much improved Firewall.

If u have these things in place and kept uodated, u will prevent such problem at bay.
LenAbAuthor Commented:
Thanks for all your comments.  I am running AVG.  Should this have found it?
LenAbAuthor Commented:
Thanks Wesley, that worked fine.  I run AVG.  Should that not have picked it up?
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