As I have already stated, I strongly advise against using any type of messenger program as it is a major vehicle for newly emerging worms/trojans/viruses.
If you must and you are having problems with your regular messenger program, you may want to consider MicroSoft Web Messenger. It is the web based clone of your regular microsoft messenger program and as long as you can still access the internet. It should work. Not totally safe but probably safer than the regular Microsoft Messenger as nothing is downloaded to your computer.