dell xps 730 broken

[Ozxx]

I dont know if this is the right place to post this but here i go.
i have a dell xps 730 and it wont start up. when i turn it on all of the fans start working really hard and loud and the computer start doing beep sounds and i also notice that the motherboard letter reads fb instead of ff which is what it says when its normally working. also when i connect the monitor it says that it has no signal.
i didnt turn on the computer for like a year and it was all dusted. i already brake it apart and clean it and still nothing.

ill appreciate some advice to try to fix it before take in it to the tech. thank you.

this is my computer >> http://en.community.dell.com/support....aspx#19155395

[cp1]

Try and find the beep codes or the "motherboard letter" codes in your manual or online and then see what error it gives you.