So my MBP is my first ever mac. I got it in August. I upgraded to Leopard the day it came out. Since then I've had so many problems. I will list them out: 1. Downloading. Since upgrading to Leopard, I cannot download .dmg files on my network. On my network, and my network only, any time I download a .dmg file (or a system update file) I get a "invalid checksum. codec overrun" when I try to mount the image. I've searched about this problem endlessly both on google and this site and cannot find a solution. The only answer I get is that it is a result of files not downloading completely. The only way I can download files is if I switch to another network near by. I think part of the reason these files do not download completely is related to problem 2. 2. Wireless issues. This is something I know lots of people are having problems with. Again, on my network only, I have constant drop outs of signal. I know it isn't a range issue, because when I am connected I always full signal and my roommates around me have no problems. When I am on my school's wireless or if I connect to my neighbor's, I have zero problems. I even switched to a completely different router (from a linksys to a netgear) and it didn't solve the problem at all. The security I've tried is WPA and WPA2 and neither change anything. I just don't know what to do anymore. I've tried everything. My roommate who's MBP was built on the same day as mine has zero issues, but he hasn't upgraded to Leopard. Problem #1 I know isn't just a Leopard thing. I don't hear a lot of people with the same problem and I've reinstalled Leopard (from scratch) about 5 times. What should I do?