Okay there isn't alot given to go off of, but if you're serious about getting to the bottom of this, there's alot of people here that can help you, if you help them in return.
First, please fill in your system specs more thoroughly. Now on to some random shots in the dark to get things rolling.
1) Is the lag you speak of consistent regardless of whatever you're doing? Or more task dependant?
2) Is the sceenshot supposed to be during a moment of lag or just a general one for sake of processes?
3) Regardless of the previous answer, try to get one of the CPU heading as well as the memory during your lag.
4) Have you looked at your event viewer to see if anything is happening in the background on a timely manner?
Lastly, what steps have you taken to troubleshoot the problem? It's never fun doing things twice...
Good luck and report back with your findings,
-Ageeb