Many applications stop responding

[Nnamegah]

Hi Pro's,

I have a MacPro from 2008, and lately I have had some annoying experiences.
A lot of applications (iTunes, MS office, even the Installer) stop responding after a little while. The beach ball comes inside

What can be done?
Yes, I have emptied the cachefiles every now and then
Yes, I have restarted with option-CMD-P-R
and yes, it helps a bit, but after some time the stopping starts again.

Who can help me with any advice, or should I just re-install all these applications eek: again).

Thanks in advance
Best,
Carlo

 

[Cindori]

repair disk permissions

 

[Nnamegah]

That might be it!

So far, so good, at least

Thx
Carlo