boot with cdrom

[mahesh]

hi all - I'm trying to put Ubuntu 14.04.6 LTS Trusty Tahr on an old pentium 3 450mhz 384ram (I know it wil b slow). the image is over a gig and my cdrom drive cant read DVDs. I cant boot normally from the BIOS as its an old pc, is there a boot disc I can use to enable usb and install off it? thanks