I´m worried because the full system scan is taking too much time than it was suppose to take. I´ve performed a full system scan with kaspersky 5.0 and it has taked approximately 4 or 5 hours, I amm not sure, but now I am performing a scan with KIS2006 and it´s about 6 hours and it´s has not yet finished. It´s even get 50% of total files scanned. If u could clarify me about this situation I would be very grateful

That does seem a long time but to give a meaningful response the size of the task and the processor speed are critical. Total memory may also be a factor.
As an example on my system with about 400.000 files spread over 4 drives all NTFS and an AMD 64 processor running at 2300MHz and 1 GB of ram it took about an hour for a full initial scan.

In my case the scan was taking too much time cause a file was corrupted and kis was blocked in this file.