MY CPU is running at 100% all the time

[GRAVATYCAT]

so my cpu is running at 100% when idle. after awhile it crashes and i boot into safe mode and then im nice and dandy. i ran malware bites and avast to scan and i found nothing. CPU: pentium D 945 GPU: radeon HD 6450 RAM :2gb

 

[neieus]

First thing you should do is find out what application is causing your cpu to run at 100% by looking at the task manager and sort the processes by CPU usages.

 

[GRAVATYCAT]

It ranges from catalyst control and avast it goes high then low and something replaces it as top sometimes I also get windows module installer and .net runtime optimization service. I've never heard of this before so I think this might be the problem

 

[neieus]

The items that are using the CPU will float up and down the list but there has to be one time that uses the most constantly.

 

[GRAVATYCAT]

Nope there is not one constantly at the top. I did another scan and now there's pups on walware bites so could this he a cause there some registry and the rest files and app extension.