unable to delete asl files

My asl log folder has filled up my hard-drive. I have done extensive research regarding how to fix this problem. But I am stuck: I cannot delete these asl files. I do not have sufficient administrative privileges to delete them. And I cannot set my account to have administrative root privileges, though I am the administrator user of the computer. I have no idea why. Part of the problem is that I do not have the install dvd that came with the computer (bought it off of ebay). I am ordering OS 10.6 hoping that installing it will take care of the problem. Do you have any ideas about gaining administrative privileges so that I can erase the asl log files that are filling up my hard-drive?