CPU 50+% usage on typicals works.

Hello , my pc specs :
Intel core 2 duo 2.33Mhz , 7gb ram ( had 4gb until last week ) , ATI radeon HD 2600 pro .
Had the windows 7 32-bit and my pc was working fine made the format and install windows 7 64-bit to be able to upgrade my memory ( 32bit was using only 3.3Mhz) .
After the 64bit installation the pc start lagging , the cpu usage is going over 80% and stays there , sometimes it is 100% and i can not move my mouse. This might happen while i am on facebook and listening radio over the internet and have some files opened or watching a movie and download something. Also the sidebar.exe uses from time to time 20-50% of CPU.

Have you looked at Task Manager or Resource Monitor to see what processes are using CPU and RAM?

Yes , it depends actually. Sometimes its the mozilla ,i think its max on 25-30% not sure or the vlc , saw it to reach 50%. Also the sidebar.exe is from the firsts programs that start to use the cpu , if i remember correct it goes something like 40+% .

Reboot, and then wait for it to bog down.

When it is running slow, take a screen shot of Task Manager processes tab, showing the CPU column sorted from most to least.

Also, when bogged down, post a screenshot of the memory tab of Resource Monitor with the Private KB tab sorted from most to least.

I was playing a game on fb had 2 more pages open , put a small video on vlc and it 5-10 secs cpu reach 100%.

I'm at a serious disadvantage because I can't read whatever language that is.

Do you have a bunch of stuff checked in the startup tab of msconfig? Try checking just your antivirus and see if that helps.

Have you recently done anti-virus and anti-malware scans?

Do you have the same problem if you go back to just 4 GB of RAM?

Did you use a retail version of 64-bit Windows for this recent install?

Its greek. I have run multiple times avast and malwarebytes did not find anything. Yes with 4gb i had the same problem. About the msconfig you are suggesting to uncheck everything and leave only the antivirus?

firefox has a huge issue with facebook. your plugin container is using tons of memory. switch to chrome or IE if yoyr on FB for a long time.