For yellow balloons try the non-stop party shop on Western Road, see if we can buy up their entire stock by Saturday...
Where can you get the bananas from?
When you switch it on, it should give the BIOS manufacturers name, usually one of Award, AMI, or Phoenix.
Check this site out to find out what the exact problem is...
http://www.amptron.com/html/bios.beepcodes.html