Folks, My MBP has been playing up recently, running slow, beach balling when it never used to, etc ,etc. I repaired permissions but to no avail. So I decided to do a clean install. Inserted my Mac OS X Leopard disk (first mistake since I realised I should've used the disks that came with the MBP .... doh!). I was then going to use my upgrade disk to Snow Leopard. I keyed in my password when asked to do so and OS asked me to press Ok as the system would then restart. All that has since happened is (1) the start up chime, (2) a bit of disk whirring, (3) a black screen then then back to (1) again, over and over and over again. Can anyone please help - I really don't want to have to shell out for a new MBP! Many thanks in advance for any assistance. PS: model is a late 2008 2.53 C2D (first model in the current design).