|"My pc was infected by PC Internet Security 2010"|
That's one of the "rogue" anti-malware programs.
What the makers of such software do is infect web sites with crap that contaminates your computer by you merely visiting the contaminated web site, or you may have gotten it when you downloaded illegally obtained software and the crap was released when you executed the download. .
One of the things that crap often does is disable things that normally work fine, such as Task Manager.
The symptoms created by the crap are all FAKED. The intention is for you to be deceived into scanning your computer with their anti-malware software - the scan is free, but you have to pay for the anti-malware software to get rid of the crap, most of which, or all of which, is crap the same "rogue" anti-malware software maker was responsible for contaminating your computer with.
The "rogue" anti-malware program is legitimate, but the method they use to try to get you to buy it is considered to be unethical. The quality of it varies from okay to poor.
Most major legitimate anti-malware programs either do not find the crap, or they do but they can't get rid of it properly. The "rogue" anti-malware makers update the method of crap contamination etc. more often than many legitimate major anti-malware programs can keep up with.
Malwarebytes specializes in getting rid of the crap and the "rogue" anti-malware program too.
Download the free version of Malwarebytes from the web, choose to save it to desktop (the main desktop screen), run the download, then run the Full scan in the resulting Malwarebytes program.
When it has finished, have it remove everything it found.
Your PC Internet Security 2010 "rogue" anti-malware program and all the crap and it's effects will probably be completely gone after you have restarted the computer.
If you can't use an internet browser on the contaminated computer without being hassled with pop ups or being re-directed to an anti-malware web site, download the free version of Malwarebytes on another computer, copy it to a flash drive, then plug the flash drive into your computer while Windows is running and choose to save the download to desktop (the main desktop screen).
The Malwarebytes Full scan will take less time to run if you run it in Safe mode, or Safe mode with networking if you need to Update it.
Press F8 repeatedly while booting - do not hold it down - and choose Safe mode, or Safe mode with networking.
The free version of Malwarebytes updates itself when you first install it, but it does not auto update itself after that.
If you need to run it in the future, you need to click on Update in the program, and update it, BEFORE you run a Full scan.
It does not have a resident module that runs all the time looking for suspicious activity, so it will not interfere with any resident module of whatever other anti-malware programs that are installed on your computer.
Sometimes the crap installed by the makers of "rogue" anti-malware programs prevents you from executing all or specific *.exe files.
If the Malwarebytes download will not run, or if the resulting installed Malwarebytes program will not run, if you rename the download file name mbamxxxxxx.exe to mbamxxxxxx.bat, or the resulting Malwarebytes program mbam.exe to mbam.bat, the download will install the program, or the program will work fine, when you double click on the *.bat file.
If you can't see the .exe file extensions, go to Control Panel - Folder Options, select the View tab, and enable Show file extensions for known file types, click on OK at the bottom of the Folder Options window.
If you keep getting crap that was made by the makers of "rogue" anti-malware programs on your computer, many people have bought the paid version of Malwarebytes - it auto updates itself, and it has a resident module that runs all the time the computer is running looking for suspicious activity.