Programs keep fighting for CPU usage.?

Question

Every once and while, my computer will get very slow. When I go to Windows Task Manager, it usually shows the CPU Usage chart as using 100% of the CPU. Sometimes the Processes tab shows a program using close to 100% of the CPU (frequently: iexplorer.exe, NettGain1200_C.exe, and svchost.exe). Then I just end the program controlling that process in the Application tab. But sometimes I don't see anything unusual in the Processor tab. In this case, I usually just log off or restart the computer entirely.

This has been happening every once in a while for a few years now, but eversince I got the Internet (which uses a USB connection to my cell phone) a few months ago, it has been happening more often. It used to be a few times a year; now it's a few times a month.

What's causing this, and how do I remedy it or stop it from happening again?

If it helps, I have a Dell Dimension 2400 PC with Windows XP: Home Edition.

Answer 1

NettGain1200_C.exe is suspicious.
Usually when the winlogon is loading a malicious dll (allocate a lot of memory) the use of CPU is going to thousand...
click in start\execute\
type regedit.exe and navigate for the path ...
HKEY_LOCAL_MACHINE\SOFTWARE\
MICROSOFT\WINDOWS NT\
CurrentVersion\Winlogon \
Notify
verify each key and your respective dlls that are registered(svchost) ... the libraries crypt32, crypnet,cscdll,wlnotify and sclgntfy are not problems...
The fact of the cell phone believes not to affect in anything, coincidence...

Answer 2

Try installing one or more spyware/adware detection utilities.

Grisoft AVG and Ad-Aware have free versions that I have found to work well.

I've had IE7 "peg out the CPU" and haven't been able to figure out how to fix other than closing it.