Problems with lagging/freezing

[Allisonbell0204]

I have a HP All-in-one and I have had several problems with it (I purchased it 4 months ago). We recently had to send it in because it went completely out. When it came back I didn't seem to notice any problems but not I have noticed it lagging and freezing. I can't even run the mouse across the screen without it freezing. Videos are choppy and lagging. Games are the same way. From my understanding a motherboard had gone out and had to be replaced. I hate to think we will have to send it in, again. Can anyone please help?? This is so frustrating. Makes it really hard for my son to complete school work with the constant problems. 

[TheOldMan]

Most AIO's are just a laptop with a big screen.  Depending on the model number it is hard to offer an explanation for what might be causing these problems.

I would suggest installing antiwalware, if it is not installed.  Windows offers free antivirus, Microsoft Defender Antivirus, all you need to do is active it. 

If that come out good, after a scan, then run the Diagnostics to see if there is a hardware problem.

To run the Diagnostics routine, Start tapping the Esc key BEFORE starting the PC and then press the start button.
Keep tapping the Esc key until a popup menu shows. Then pick Diagnostics from that popup menu, F2.
Report back with the results.