Options for my (partially dead) computer

[Byzantine Emperor]

Call me sad, but I really was sad when I learned my motherboard kicked the bucket. All my hard modding was on that machine! I've lost all my weeks of work, but more importantly I am now only limited to my laptop, (that I am typing this on) which is far, far worse in performance than my PC. A LOT.

OK, the choices I have:
1.Pay £200 for a new motherboard. Same machine.
2.Pay £300 for a new motherboard, casing and processor ( I do not know how good the processor is. ) and a warranty for 3 years.
3.A new computer. An option that really should be avoided because of the cost.
4.Forget the computer. (Another option that I really do not want to take)

This is not spam. I paid (or my mum and dad paid) £1000 plus for this computer, and it is good:
DELL Dimension 9100
3.2GHZ Processor
Windows XP Home Edition
1024MB memory
250GB 7200RPM Hard drive
DVD drive
256MB Nvidia GE Force graphics card (might have needed upgrading?)
Soundblaster Live 24-bit sound card

Please forgive me if there is a forum for techy stuff like this, because I do not know of one