Dell Inspiron 600m (Pentium 1.6 Ghz, 512 MB RAM, 60GB Hard Disk (50% free), Windows XP)

Once I start using internet (dial up), CPU usage reaches 100%. According to Windows task manager, primary users of memory and cpu are opera.exe (firefox and IE as well if I use them), Mcshield.exe, explorer.exe and svchost.exe. I tried changing priority of Mcshield.exe from high to normal but the system didn't allow me. I am not running any windows media player, messenger or p2p exchange software etc.- just simple browsing. Even if I kill opera.exe and stop using internet, CPU usage remains 100%.

I have scanned using McAfee anti-virus. I have already disabled automatic windows updates. Ran a dell tune up program to clean up; tried to defragment disk but the system's analysis was that it wasn't required.

I don't know if it's relevant but my laptop gets quite hot though there hasn't been any warning/automatic shutdown.

Can anyone suggest a solution ? Thanks in advance.

if CPU uses is 100% then your computer is suffering from viruses and spy wares so scan it using anti virus with update. i hope it works.

After scanning for viruses and spyware I would get rid of McAfee and install a free antivirus like AVG or AVAST or AVIRA. McAfee is a memory hog and the free AV programs do not use as much memory and work just as well as Mcafee. Myself, I use AVG and I have no problems and I am using a system with similar specs to yours.

PS. Also run Glary Utilities. It is free and it will clean up your pc of useless files and clean your registry.

try to use and online antivirus, housecall i suggest

Thanks for the replies. I have scanned it (not a single virus/pup etc was found) and run gladys utilities - the problem remains.

I still have a year left on my subscription of McAfee's security center. I can uninstall it but I want to be sure that it is the root of the problem. The thing is that there are multiple files (including mcshield.exe from McAfee) hogging cpu usage and memory and they keep on fluctuating. As I write this, there's a process - System (PID 4) that's in range of 1% - 75% CPU usage. I have checked for svchost.exe and it is not the source of high CPU usage.

Any other suggestions ?

Make your system to a bak,then reinstall the system.After that,if the CPU still as 100%,then tell me.

The problem was overheating - got a new fan and everything's back to normal.