CPU peaks randomly

[TruenoICE]

Hello everyone, so I built my sister a PC so she can game as well, while using some old recycled parts. Everything went well minus having to RMA the PSU but other than that, it worked fine. Since it's an older PC it did take time to turn on and be usable but while using it, I noted that the CPU usage and RAM usage peaked randomly and often at times, even during idle.
The Specs are:
IPIBL-LB motherboard, Intel Duo2 E6600, 8 GB, XFX R5 260X, EVGA 650W Full-Modular PSU
What can be done to keep the CPU from throttling?
PS: Also nothing is overclocked.

 

[turkey3_scratch]

That's normal behavior for when a program uses a lot of processing power in a quick amount of time, such as loading and arranging a couple of webpages.

 

[TruenoICE]

I apologize for not getting back to this sooner, been busy with work and family. Any who, thanks for the suggestion. I'll try removing any old software we don't use(or least not have it start up unless needed). I did have another thought come to mind, which was getting a new HDD to replace the old recycled ones. Would that affect the computer in any way, and would i need to re-download Windows to it? Again sorry for the delay and bringing up new questions. Thanks again for helping. Will update what I do as soon as possible.

 

[turkey3_scratch]

Hard drive wouldn't have to do with CPU usage spikes.