Be very careful with buying used laptops. A used laptop is a very risky purchase compared to a used desktop. By its very nature of mobility its hard to say what your buying.
Ask yourself when looking at a used laptop...
How many times was this thing dropped ?
How often did this person use it on their bed with blankets sufficating it and causing heat issues ?
Did it get left often in a hot car in the summer.
There is no way of knowing the answer to any of these questions and this is why a used laptop is always a risky deal.
Also just as an FYI the HP DV6000 series is plagued with defective motherboard issues. Sad part is that even though its a known defect HP did not issue a recall. Also the replacement motherboards that were issued for those under warranty had the exact same problem.
http://h30434.www3.hp.com/t5/Noteboo...ty/td-p/107304
I dealt with this issue a lot and is one of the primary examples why I tell people to run from HP computers.