I have the Windows Live Messenger and commonly I run 2 accounts.
Ultimately I found that WLM requires a lot of memory RAM and slows my computer. Before this didn't happened to my computer but I don't know why it happens.

I think it's becuz I have many MP!L plug ins installed, am I right?
or whats the cause for this?

It could be a number of reasons. Do you mean it is taking up a lot of CPU and slowing down your computer?

Well, theres nothing you can really do to stop this other than to just use one account at a time. Maybe set times on which account to log into.

It could also be the ammount of plug-ins you have, but i highly doubt it. As when you use MSN Messenger Live with Plus! installed not all the plug-ins run all the time. Most of them only run when needed.

Like i said the only thing i can think of it to just use one account at a time. Messenger Live is a big prog and will take a lot of CPU usage just running one.

I agree with darkme. My mom's computer is a fairly old (but still XP) and WLM slows down the comp quite a bit. When all 3 accounts are on, the computer goes to crawling speed. MSN Messenger 7.5 was a lot less harsh on the computers, but WLM is a lot better for us.

But why does it slow our comps down that much?

because there is a memory leak off some sort in WLM, which inspite off the beta testers complaints microsoft didn't fix