Nokia :: N96 - Gets Stuck On Using Applications?

I've got this wonderful N96 phone, lately it has developed a problem, the phone works just fine when I restart it. But as I open more applications, the phone gets a bit slower, mostly I use opera mini, that might be normal because the memory is limited, but closing the applications doesn't help. After using the phone for a few hours, there comes a point when it would just kinda hang, the clock display on the upper right corner disappears, I can access the menu but when I try to open an application, nothing happens, I have to restart the phone to make it work again. This happens 7 or 8 times a day, and its annoying because the phone stops responding when I need it the most, like using a dictionary, opera mini and fring at the same time. Even if I close those apps, it won't help, it needs a restart.