Although my computer begins start up it gets stuck in a blank screen - what can I do? My son said he though someone had hackered into his messenger as there were messages not typed by him and so shut down . Since then we haven´t been able to log in bacause the screen remains blank.

Is there a flashing cursor in the top left hand side of your monitor?

Hi, we now have several locations that are capable of accessing the Yahoo Instant Messaging feature.
Yahoo Messenger itself, plus Yahoo Web Messenger, Yahoo All New Mail, My Yahoo, your Mobile phone, plus any other computer.etc etc.
Yahoo classifies all these programs as different 'locations or devices'
Yahoo currently do not allow you to have 2 open and active at the same time. If you have one open, and then move to another, one will close and you get a message telling you that you have been signed out. You CAN have Messenger and Mail open together as long as your status is set to "offline" in MAIL by using the drop-box next to your name and selecting 'Sign out of chat'. ( your chat contacts will remove themselves from the inbox until you make yourself 'available' again.)
Please note:
You may think you are signed out of Messenger when this is not the case.
Hitting the 'X' when you close the Messenger page does not sign you out of Messenger it only closes that page - you have to Exit Messenger by right clicking the icon in the system tray.and selecting 'Exit' I suggest you make this setting. > (left click) Messenger > Preferences > General - check box "sign out of Messenger when I close the main window" > Apply > OK.
If the above does not apply and you suspect your account is being used by a hacker. When you get signed out, close all your Yahoo programs and type your name into this software. Hit "GO" and hopefully it will show you as "offline".
If not, contact Yahoo customer services
http://detectinvisible.com/

Install latest version of java.. Thnx

i recommend you contact Microsoft support for assistance. The problem here is that the hacker responsible likely has somehow acquired user login information. I hope Microsoft can provide support for you since dealing with hackers in any respect is tricky business.

Use Your Webcam in Yahoo Messenger Step1Head to the Yahoo home page, turn on Yahoo Messenger using the 'Messenger' link and log in using your account name and password. You'll need to create an account if you haven't done so already (see Resources below). Step2Click the 'Messenger' followed by the 'Start My Webcam' option. This will load your webcam, and is among the ways you can get your webcam to begin broadcasting. Step3Click on the camera icon that appears in a chat window while you are talking to a friend. Step4Click on a contact from your Contact List, then click 'Invite to View My Webcam.' This opens a new IM window with your webcam active. Step5Click the 'View Webcam' link while talking to others in IM. This will allow you to see their webcams. Step6Use the 'Super Webcam' mode when you want to send and receive high-quality images and feeds. Broadband makes it possible to see one another in very high resolution, although even with high-end broadband your computer may slow down a bit because of the amount of memory and processing power this requires. Step7Click 'Webcam' followed by the 'Who's Watching Me' button to see which of your friends is receiving your webcam's feed.

which OS do you use? if its any of windows, do so:
install these free programs from download.com
1. avira antivirus free
2. spybot sd free
3. advanced windows care free 3.0 and higher

run all, you will be protected as you must be. my winxp works with these great, and i don't get nothing that dont belog to my comp at all. its really great progs, and free af course. hope i helped

get the great anti virus and scan it 3 times,, download first this link and install first the anti-virus
http://www.softpedia.com/get/Antivirus/Avast-Home-Edition.shtml

if he shoved it in really far take it 2 someone to help you.. if its in there not so far but is stuck tak something really thin and put it under and pop the game out