Photoshop reacts very very slowly

Hello,

We have Photoshop running at the company here. Recently Photoshop is reacting very very slowly (commands and movements keep "hanging" or execute in small timelapses). We can not use it like this for the moment. No re-insstallation or so was done. Our internet and dataspeed is working correctly. Any one who knows what the problem can be? Thanks!

regards,

Wim