Hi LEIzie, I am aware the auto updater may not show the NM 5.1 update to everyone. Since you have a Linksys Router, You can download NM 5.1 for free at http://www.purenetworks.com/download, even though it says it a free trial. (Those that have Linksys Routers get some features for free) If you have a Pro/Essentals License, you do not have to enter your license key again as long as you don't uninstall NM 5.0 before you install 5.1.
My Cisco Network Magic Configuration: Router: D-Link WBR-2310 A1 FW:1.04, connected to Comcast High Speed Internet Desktop, iMac: NM is on the Windows Partition, using Boot camp to access Windows, Windows 7 Pro 32-bit RTM, Broadcom Wireless N Card, McAfee Personal Firewall 2009, Mac Partition of the iMac is using Mac OS X 10.6.1 Snow Leopard Laptop: Windows XP Pro SP3, Intel PRO/Wireless 2200BG, McAfee Personal Firewall 2008
Please note that though I am a beta tester for Network Magic, I am not a employee of Linksys/Cisco and am volunteering my time here to help other NM users.