Try reinstalling your browsers to reset those back to the defaults. That would be much easier. The defaults should then allow you to download without problems. Then you can go right to the download for the Yahoo messenger seen at Download Yahoo! Messenger
The page seen there checks out security wise in case you were going to a link with ??? marks. The official site is seen at http://messenger.yahoo.com/?mdevt=sr1373
OS Windows 7 Ultimate x64, XP Mode, W8 RP VM, Linux Mint Debian 2nd OS HD- 7 Pro x64 second case CPU AMD Phenom II X4 975 Deneb 3.6ghz - 965 on new mini tower Motherboard Gigabyte GA-790XTA-UD4 Memory Kingston Hyper X DDR3 1600 1.5v 16gb - Mushkin on 2nd build Graphics Card MSI HD Radeon 5750 1gb - MSI HD Radeon 6450 on mini tower Sound Card Creative Labs X-Fi XtremeGamer - Realtek onooard 2nd case Monitor(s) Displays 2 x Acer P191W 19" widesscreen - HP 20" widescreen mini towe Screen Resolution 1440x900 native - 1600x1024 on 7 Pro x64 build
Keyboard Microsoft Recusa Razor - MS Comfort 3000 on second build Mouse MS Trackball Explorer - A4TECH dual scroll wheel trackball PSU Corsair 750TX - primary / Corsair CX600 - second Case Antec 900-2 - SSD compatible / NZXT Vulcan mini tower Cooling Zalman CNPS9900A Hard Drives Primary Ultimate x64 build-
WD Black Edition 1tb Sata 6.0 = 2
WD Black Edition 1tb Sata 3.0 = 2 (OS drives)
WD 1tb Green Power sata = 2 1 external
usb flash drives = 18
Second 7 Pro x64 mini tower-
WD Caviar SE 500gb sata II single drive presen Internet Speed 30mbps upgrade - primary hard wired - mini tower usb WiFi