everytime i sign onto msn(i have plus installed) it opens the main window and a message that says something like "you have to enter your old password for the encrypted files otherwise  no logs will be made for this session" comes up but then after about 3 seconds of messenger being signed on it closes me out all together. Anyone know what is happening?

first of all, did you install any new plugins prior to when this started happening? 
also, did you try both - 1. putting your password in, 2. just pressing ok without putting in the password. or does it sign you out each time regardless if you do any of these things?

if it does, you can try a couple of things:

try running msn without plus!, if it lets you sign in, than i suggest you -> uninstall plus along with the prefferences, and reinstall it.

if msn signs you out even when plus is not running, try a clean install of msn (uninstall msn and than install it again).

most importantly, which versions of msn and plus! are you using?

check here for the newest versions. if you are not using the lastest ones - do an update:
http://messenger.msn.com/download/

http://www.msgplus.net/download.php

Well i've tried putting my password in but usually it doesn't even give me time to. plus now theres another message that pops up but i don't ever have time to read it so i have no idea what it says.

I am using the newest version of plus also and when i tried to use msn without it msn would just say "msn messenger has encountered a problem and needs to close" every time. So thats why i downloaded plus hoping it would help. I did try to uninstall plus and download it again and i've done the same thing for regular msn also but nothings worked.

plus, even though it is a great add-on program for msn, is not intended for and does not fix msn problems. so whether you installed it or not, it would not help solve your msn problem.

i searched the web and these forums for a possible solution and found that your problem is quite common without a specific fix...
i found, basically all possible suggestions, on this site:
http://www.askmarvin.ca/forums/index.php?showtopic=199

read it thoroughly.. and see if anything on there helps you out.
you can post again if anything did help so that others may also have a solution , or if nothing helps, than post again too...
perhaps somebody else on this forum has a better idea of how to solve your problem

Edit: you can also send a message to msn support by clicking here

Ok well first of all thank you for taking your time out to help me with this problem. But when i went to look at that link i couldn't find my problem really. I'm pretty sure that its my account now because when i tried signing in with my boyfriends account it worked and stayed open. Do you think if i took my email off of the "save my password" thing it would work? I don't really know whats wrong with my accoutn because it worked on another computer

EDIT- ok somehow i got it working and it stayed signed in on my account, but stupidly i decided i should sign out and try to sign in again to see if the problem was fixed and it wasn't so i don't have any idea whats going on.