"Random" High CPU Usage

[Nexen]

I've tried searching around a bit before posting this, but couldn't really find anything. My issue involves my CPU usage suddenly sky rocketing to 60-80% when I'm watching streaming videos online or just trying to play a game. My computer runs very smoothly when watching the videos for like 30 mins-1 hour at a time, then suddenly gets bogged down with high CPU usage. High CPU usage lasts for about, 5-10 minutes or so, then eventually goes back to normal. Similar case with games, but high cpu usage happens more frequently. I noticed when playing games, a bunch of svc host stuff appears on the resource monitor when it starts to lag.

I've downloaded process explorer, and nothing weird pops up when my CPU is getting throttled. Just the programs I'm already using start using more CPU resources. A friend of mine mentioned it might be things like EIST, speed step involving my CPU. I downloaded CPU Z and noticed my CPU jumps from 1.6 GHZ to 2.4 GHZ randomly.

I'll post my cpu specs and what I've already tried to do thus far.

OS: Windows Vista Home Premium 64 Bit with Service Pack 1
CPU:Intel Core 2 Quad CPU Q6600 @ 2.4 GHZ
Motherboard: MSI P6N nForce 650i SLI Chipset
RAM: 2 GB DDR2 800
Video Card: NVIDIA GeForce 8600 GT 512MB Dedicated Vid Memory (Latest Drivers June 23 v 7.15.11.7519)
Sound Card: Onboard Realtek ALC888 HD Audio Flexible 8-channel (Latest Drivers 9/9/08 v 6.0.1.5700)
Hard Drive: 500GB SATA-II 3.0Gb/s 8MB Cache 7200RPM HDD

The things I've already tried:
1) Changing priority of performance from background services to programs, and vice versa.
2) Changing virtual memory to a static 4096 MB-4096MB and allowing Vista to do it manually.
3) Issue with audiodg.exe eating up massive resources for some unknown reason, I disabled special effects on my speakers, disabled my microphone, and turned off Realtek programs on Startup.
4) Switched power options to high performance ( No clue what this even changes on a desktop)
5) Disabled/enabled SuperFetch
6) Complete diagnostic of my RAM with the vista utility.
7) System health report of my computer
8) Removed nProtect GameGuard ( Issues with memory leaks, staying on when game is off, concealing itself within windows processes to do "security checks?")
9) Fully updated via Automatic Windows Update.
10) Hard Drive is defragged and error scanned.
11) Virus Scanned with AVG 8, and found only tracking cookies. I do not have this autoscanning, and already deleted it.

Any help is appreciated, and if you need any more information like my dxdiag log, please ask for it. I'm fairly new to Vista and haven't really tampered with my BIOS on this computer, but have some knowledge when dealing with computers.

 

[Nexen]

Nobody has any clue at all to what the problem could be?

 

[TheKub]

When you are running processexplorer are there any programs beneath the svchost (as in clicking on the + symbol) entry that is using a large chunk of your CPU? There will be multiple svchost entries.

 

[Nexen]

Due to something really screwy happening, I was forced to reinstall vista. I was disabling page file to see how it would run without it, and it started getting choppy graphics while watching videos much sooner. However, once I tried to undo that, It mentioned something about replacing my current pagefile system file, and I clicked yes without thinking it would cause any real harm. Well, after I did that, all my system restore points were gone and it seemed as if page file no longer worked period.

Even after reinstalling vista, it still lags up eventually when watching videos. The svchost.exe files weren't visibly eating up resources is the problem. Whenever they ran, the svchost.exe services weren't eating major resources or memory. It's just a lot of stuff starts loading and becomes visible in the resource monitor and it starts lagging up. The programs that I've been running throughout the whole time just start eating up more CPU usage for no reason i.e. firefox, task manager, msn messenger.

I'll still list the svchost.exe files that popped up before I reinstalled vista. I haven't had a chance to check it after reinstalling.

scvhost.exe localservicenetworkrestricted (sometimes shows up twice)
svchost.exe netsvcs
svchost.exe Network Service
svchost.exe dcomlaunch

Along with these, I notice task scheduler running also. I checked before and during the major cpu usage, and the same "currently" running tasks are on. I didn't go through what each task was and what triggered it.