Hi radek135
Here are some possible paths for you to take.
In Internet properties go to -
General tab -
Browsing history - press - Settings button.
Where it says - disk space to use - change this to 250(MB) or lower.
History - days keep page - change as you require.
Next - house keeping.
Start button - programs - accessories - system tools - Disk cleanup - run this weekly.
Try downloading firefox for your Internet browsing.
Your running processes are accessed by pressing -
Ctrl - Alt - del. Here under the processes tab you can see Memory usage - There is a end process button allowing you to close highlighted programs -careful here as closing e.g. explorer.exe (or other important processes) will loose you control of pc. Internet explorer is listed as iexplorer and can be closed from here.
Hope this helps.
Silverhelper.