freezing at random , very slow

Hello all,

I got a friend with an Apple iMac (2010). I’m not an Apple user ( I’m an experienced user in windows though...)

The iMac was upgraded last year to a i7 with 16 GB of RAM.

It worked just fine till last week (after a moving from one building to another, the iMac was strapped and secured in transit).

When booting the system it takes up to an half hour to get to the log in screen….

Once you’re in, sometimes an app opens like normal, 10 seconds later the same app will not open … it takes like 15 minutes to open, you just can’t work with the system in this state and it’s freezing at random times.

What I noticed when booting, the upper side of the screen is normal (blue-purple) the bottom is white with lines and white blue purple and yellow squares) so I was thinking this is a GPU problem?

But thats only when booting, not when we use the system…

When I check the RAM, HDD usage and the CPU usage everything is normal. But like I said before, I’m not an Apple user so I don’t know where to look further (like I know what to do with windows machines)

fan(s) are spinning normal..

Can someone help me out?

Thanks in advance

Kind regards

Kevin