Hey,
What Qosmio notebook you have exactly?
Regarding the overheating issue maybe the dust is blocking a good air circulation. You should clean your notebook with compressed air spray. This can blow out the dust from the cooling ventilators. Compressed air spray can be bought from every computer shop normally.
Regarding your other question, can you boot from DVD for example? You should try to remove the upper and lower filters in registry:
http://support.microsoft.com/kb/314060
Maybe there is also dust on the lens. You should clean the lens of CD/DVD drive using a microfiber cloth. It’s worth a try!
