I find it odd that you state you run no scripts in the same sentence that you claim to "possibly" use one. Also, your claim contradicts your very previous post where you said you were using upp. Clearly gtsdll is not the only script you use. Now you can see why I find it hard to believe your situation. Are you positive you're running a clean install of mIRC from http://www.mirc.com
In your clean mIRC, type the following in any window:
//echo -a $version $os $md5($mircexe,2) $script(0) $dll(0) $com(0)
Paste the resulting line here. Then make sure that you actually keep it on and reproduce the issue again with the clean install.
On a sidenote, it would help if you more accurately described "freezing". What are you doing when it "freezes". How long does it "freeze" for? Indefinitely? Or for a few seconds?
And if it matters, I'm able to run mIRC without any freezing issues on Windows7 64bit.