PC will not boot with Laptop HDD connect

Hello All,
I have a ACER laptop with a 60 Gig HDD and it is refusung to boot in the laptop.
I have recently purchaed a 2.5 to 3.5 IDE HDD adaptor. My plan was to mate my laptop HDD into my PC as a slave (secondary position on the IDE cable).
I did a bit of back ground testing initially to ensure my ‘idea’ would work. The PC will see each HDD when individually connected (the laptop HDD fails – as to be expected – corrupted “system32\config\system” file). But when i make the 3.5 HDD the Master (which i need to boot off) and the laptop (2.5) HDD as a secondary on the IDE cable, the PC doesnot recognise that any HDD is connected?
Any ideas on how i can get around this issue and retrieve the data off the laptop HDD.
Cheers.