New drive...
Compass.....
If it is heat related the problem wont be fixed by a new drive (why would one drive be hotter than another and can you assure your new drive runs cooler ?)...
However it does sound like your disk is on the way out - to me it sounds like its having trouble maintaining rotation speed). However...
The good news is if your existing disk is not totally gone when you purchase your new disk we can copy over an image of what you have direct onto your new disk so there is no need for a fresh install.
If you want to do this PM me and I will let you know what freeware you need to download and how to do this it will save losing the OS/Applications/Data you already have.
Cheers
Jofm5