Premiere elements lagging/ jumping unable to edit

I have premiere elements 14 and am trying to edit a video.

I put the raw footage into the software and when I try to edit, the video is lagging, jumping and jerking. The video becomes so slow it lags behind the audio.

I have exported a small clip, and there is no lagging when exported, just when trying to edit the video. It's so bad, it is impossible to edit.

I have a windows 10 computer, I have tried uninstalling the last update and that didn't make any difference.

I have not tried to add any text or effects- it is the raw footage that is lagging.

I've gone back and watched previous videos I have edited and exported through the software which previously had no problems and now are lagging too.

I have enough storage space on the hard drive where the raw footage is and where it will be exported to.

I've tried rendering the footage but that does not make any difference. I have no, red, green, yellow or orange lines above the footage.

The footage is from a DSLR camera and have never had problems like this before. It worked fine last week and now isn't.

Any suggestions on how to overcome this problem?