Install software musical interface

Without knowing the make and model,we can't give specific advice. However, multiple different notrs being triggered by one key doesn't sound like cleaning the key contacys will fix it. Also, to clean the contacts will require disassembly of the unit. If yopu're not used to doinf so, I'd suggesy taking it in for repair.

Turn off "Casio Chord" &/or autoaccompaniment

It's probably your keyboard. Some keyboards are limited with it's polyponic capabilities. Some can play many notes at one time, some cut out when it reaches it's limits. Check your manual for specifications.

Read your manual regarding "fingered chords" and similar subjects. It sounds like you are in a single fingered chord mode...

This is a midi lockup problem with conflict somewhere in your setup. Have you switched midi local off on the keyboard?

In playing fast you have to make sure to release the note fully and let the key come up. These keys have TWO contacts that are used in the scheme to measure note velocity. If BOTH contacts don't open, the note will NOT re-fire. The second symptom you have written would be a characteristic if one of the disconnect diodes has shorted. These diodes direct the strobe signals that scan the matrix of key contacts to avoid other octaves responding when multiple keys are depressed including those in other octaves. Servicing of the unit is required. It is unlikely you have the tools to DIY this problem. ONE THING to try is to tip the unit and gently tap it to see if some debris MIGHT have fallen in that may be shorting some of the matrix connections.

Verify that one of the automatic chord modes is not active. If you find other combinations triggering other notes, download this scvhematic showing TYPICAL Casio key matrix scanning:

http://elektrotanya.com/casio_wk-1200.pdf/download.html

The matrix is shown on page 5. It could be one of the disconnect diodes has failed. These diodes shown below the matrix on page 5 prevent crossing between multiple notes held during scanning so each can be individually scanned. Not there are TWO contacts per key and this is used to sense key velocity as one closes before the other.

The BUP is an archiving format proprietary to the Yamaha apparently containg styles as well as note data and conversion is really not easy.

If you can get the instrument itself to spill out MIDI and use a MIDI interface and software to capture it on the PC is the best plan.

Once it is in SMF format you can play it on the PC.

how can i play .bup file in computer?

ok here is the solution!!!!!!!!

• we should have a mic pin and audio cable as shown in this pic
• 
connect these cables,and connect big pin to the piano and small pin to the computer (mic or input jack)

now take windows movie maker (start-all programs-windows movie maker). click on narrate timeline (as a mic icon below windows movie maker).

now click start narration on the pc and play your song on the piano. you can see input level highlights. now your song is recording. when your song completes click stop narration and save to the pc. walah if you can't understand this say to me. i can add video. sry for my worst english

IF every key sounds like it is doing that, you may have two voices selected with one of them being transposed.

You may have an "effect" turned on that generates a chorus, layered or multiple voice sounds.