Win 7 extremly slow, even after clean install. CPU running low, RAM ok

Hey guys, I'm new here, and I really need yours help. Two months ago my computer started crashing on startup, BSOD, and after first crash, I boot it up again, and than works normally, like nothing happend. But I wanted to fix that, and I shut down all services on startup, that aren't related to Windows and I used used three antivirus programs, all showing no virusis in system. Than I updated all drivers, as BSOD code was some kind of problem with video graphics, even used some registry cleaners and Windows didn't crash any more. But than real problem showed up. Windows started to be very slow, and unresponsive, to open page in browser, it needs like 5 minutes, simplest task became too hard to do with my computer. I don't use it for gaming, just simpel stuff. I cleaned all the dust inside computer, but all the same. I couldn't deal with that any more, so I decided that it's time for fresh start.

That's why, I decided to do a clean install of Windows. On my great surprise, it's still slow as it was before clean install! Usage of CPU is never above 50%, and RAM also. I really don't know what to do next. Any help is welcomed! Thanks!

System spec: CPU - Pentium(R) Dual-Core CPU E6500 @ 2.93GHz
Motherboard - ASRock G31M-VS2
RAM - 4GB
HDD - WDC WD5000AAKS-00WWPA0 ATA Device
Graphics card - AMD Radeon HD5450
OS - Microsoft Windows 7 Home Premium 32-bit

Did you install 3 antivirus apps just like before the re-install?

Open Resource Monitor and switch to CPU tab and sort Processes and Services by CPU and take a screenshot. Also switch to Memory tab and sort by Working Set and take another screenshot. Post both here. Screenshots and Files - Upload and Post in Seven Forums

Also try a clean startup - Troubleshoot Application Conflicts by Performing a Clean Startup

Hey Gokay, thanks for help. Thanks for clear instructions. I did clean startup even before I did clean installation of Win7, and than again after new install and it didn't help, it's still very slow. I didn't install antivirus after new install, because computer is too slow, and it's basically blank, without any additional programs. Here's screenshots you asked

Hmm, CPU and RAM is totally alright.

Are there any unexpected high read/writes in Disk tab? And a screenshot of Performance tab of Task Manager please.

Load defaults in BIOS. How to Clear Your Computer?s CMOS to Reset BIOS Settings

Then select High Performance power plan (if you haven't already) - Power Plan Settings - Change
Also download and run HWInfo with sensors-only and keep an eye on temperatures and clocks.

Next would be some hardware checks - Troubleshooting Steps for Windows 7

I did ''load bios defaults'' and It's still the same. I did High performance power plan and nothing changed. I will do hardware checks tomorrow, because it takes hours with my computer to do it. I did install HWinfo, but I don't know what those values mean, I see clocks, but not temperature, I will upload screenshot. But here are performance screenshots, CPU spikes randomly, does it mean something?