Lock Pages was enabled by default for the account the SQL is running on 🙁

I've also found the Dynamic Cache Service but nothing changed, SQL server still uses 20-200Mb memory...

As far as I know that is not available in Standard edition

So there is no solution for this kind of problem, the system useage is minimal, page file is hardly used but the OS keep paging out memory... Aren't there...

Yes, there are we can not afford to use a server dedicated for SQL only but as I mentioned there are more than 4G free memory and the sql server...

I did, but we are using 32bit OS not 64bit, I read almost everything I found regarding this issue, but nothing helped, there are some other applications but there are...

There are no limit on sql server memory usage, it's running with default settings:

Minimum was 0Mb increased it to 512Mb without any success

Maximum is: 2147483647Mb