Computer Intermittently Freezes for a Few Seconds

Hello,

Sorry if this is in the wrong section, I wasn't completely sure where to put this topic.

My desktop (running Vista x32) has started to freeze every so often for about 2-6 seconds. It seems to happen more often when playing some games (such as Warframe) but never happens when playing others (such as Dark Souls), and also never happens when watching a video on VLC. It also tends to hang when I open a new internet page or tab, or when I try and to browse through my computer (such as my C: folder), or even when I right click to try and copy and paste something. I have tried dusting out my tower but that didn't help. I ran Cupid HW Monitor, and nothing is overheating. I looked at my processes in Task Manager and nothing is hogging the resources. I also made sure all of my drivers are up to date. I ran scans with my Malwarebytes and Microsoft Security and both came up clean.

I'm not sure what to do from this point. Any help is much appreciated.

Here are my specs (taken from dxdiag):

Dell XPS 420
Vista x32
Intel Core 2 Quad CPU Q6600 @2.4GHz
3326 MB RAM
Direct X 11

ATI Radeon HD 5700 Series



Thank you