That error can be caused by
1. Complete lack of free space on the hard drive - you will I presume know if this is the case
2. Bad Memory in otherwords a failed memory stick
In your laptop there are two memory sticks
DIMM A requires you to remove the keyboard - this is not a simple job, if you are not used to working on laptops
DIMM B is simple and is underneath a panel on the base of the laptop
See this and it is worth a try removing DIMM Bhttp://support.dell....y.htm#wp1084976
3. The failed hard drive
4. Another problem such as a driver error.
Try the DIMM B first and then see with that removed you can get a boot.
If you know that the hard drive has simply run out of free space, then the solotion is different.
When you have done that we will carry out one more check on the hard drive if there is no luck with the ram