the trouble is, when you burn a music cd, the mp3's/wma are converted into CDA (CD Audio) and normally grow in size....just try burning it, it will more than likely be to big, but you could remove some of the tracks you dont like so much or just have it on sperate disks.

a lot of newer players support mp3, which means you can fit loads of tunes on a CD.

another option if your hi-fi is in the same room is to buy a cable with one end male headphone jack, other end male RCA jack and link the output from your PC to the AUX input on the hi-fi

yet another solution is to buy a USB FM radio transmitter for your pc (about £20)
and tune you hi-fi into it....then you can stream music straight to the hi-fi from the computer.

dabs.com - Belkin Tunecast II FM Transmitter (F8V3080EA)