Karcher 2.94 has stopped working?

I was cleaning paving stones and had been using it for about 1.5hrs and it just stopped mid clean. It will still pulse when turned on. The water hose was not blocked and the power cord was not kinked. I have noticed oil on the paving. It has always been stored upright and emptied out before storage and stored indoors. Have used it 3 times in total over 3 years for less than two hours each time. Is there anyway I can fix it, although I'm not very mechanical.
After buying the posts on here, I'm really sorry I bought a Karcher. Should I have paid less for an Argos one which sounds a lot more reliable.