Edit your post to remove the tag. That kind of personal info is not allowed on this public forum. If you are still under warranty, use the Support page to contact Dell Support. That model is more a laptop than desktop. Since everything is integrated on the mainboard, it is very hard to diagnose without any monitor and any failures usually mean a big expense that would not be practical. It might be time to think about replacing it with a new computer. Does it have a display port or hdmi out port you can use to connect another monitor?  

Hi Mary, Tag Removed. No ports i'm afraid... looks like new computer is on the cards..

Regards