[wlug] laptop problem

Hi All. My machine began behaving badly. It appeared to run out of memory then totally lock up. I ran "Memtest outcome was 10 tests no errors. I replaced the hard drive with no difference being made. A simple example of one the problems was the live disc install for Feisty. Disc took forever to load then when install selected the furthest it ever went was to detecting file systems then it just quit or looped or locked. The proccessor is incredibly hot with constant stream over very hot air being forced out by the fan. The fan appears to ok as do the airways. Can anyone venture a fix for this??? Regards John