Startup disk full

My disk is full with files categorised as "other" in the About this Mac window. How do I find these and delete them ? The iMac dates from 2007 so I am sure is full of surplus files etc

I am running Yosemite 10,10,3, Intel 2.8 GHz core 2 duo

Please read:

https://support.apple.com/en-us/HT202867

- Nick

Thanks. It looks as if I have almost 700GB of sparse bundles which are using up 95% of my HD. Not sure where these came from or whether I need them. Any advice ?

Sparse bundles are essentially disk images that are similar to the disk images commonly downloaded when someone downloads software. They are also used if Time Machine is backing up to a Time Capsule or other network drive.

You'll probably need to open the files to see what they contain. It could be almost anything. Does where they are on the hard drive (what folder) give you any clue what they are? For example, those that are in the Downloads folder are likely to be software that has previously been downloaded.

There are over 2000 files, all in the Users folder. When I open one it contains what looks like gibberish (ˆfkLi‡m‘l±¡d≠ÅÚ„„˙e”∂~t.........) spread over at least 1000 lines

Are you backing up using Time Machine with the backup disk disconnected ?
What are the names of the Sparsebundles ?

Cheers ... McBie