Rebooting snow leopard

Can someone help me I've installed windows on my mac and now want to go back to snow leopard and when I've tried booting off my disc it just goes to spinnig wheel then after so long you can hear my SuperDrive spinning the stopping it does this then turn off after about 30 minutes I'be tried everything but I can't get into nvram mode to rest that if anyone could help their..... But the main problem is when I go into V mode I get these errors
Sam multimedia: read or write failed, sense_key = 0x03, asc = 0x02, ascq = 0x00 and I also get disk1s3: I/O and could not unlock playlist

So if anyone could help me with these it be muc appreciated...... Thanks

Got a MacBook, MacBook Pro, iMac or Mini?

If so the optical drive has failed if it is a full retail install DVD of SL, black colour. These model use slot loaders which do seem to have a high failure rate. Always helps if you provide full details.

It's the new white mac unibody with a slot drive but it reads other discs fine so I can't see it been the drive that's broke because it still reads my windows disc Soo I don't know

CDs are easier to read than DL DVDs which is what Snow Leopard is. Make an appointment at the Genius Bar and take your SL disc along.

Cheers will this cost me running short on budget since ive just bought this mac

Take it back as it will be under warranty and have it checked out.