What kind of laptop do you have? Did the overheating happen during the
upgrade?

About 5 years ago when I had the case of of about a 3 year old desktop
computer I noticed and had to replace a fan that didn't work anymore, bad
bearings. They make defective bearings and they end up in computer fans. It
working in Windows and not Ubuntu sounds like something else but it could
be on the edge of going bad permanently.

Does it do it from the Live CD? Have you tried other flavors of Ubuntu or other
Linux? I remember when some would make my old lap top CD drive run too fast.

help i just installed ubuntu, though a windows installer, it will boot to the
purple screen but not let me in.

Presumably you did this through Windows and was guided through setting
up where you set your location, size that you wanted to allocate to
Ubuntu, user name, password etc ? So now you have the choice of going
into Windows or Ubuntu when the PC starts up but the Ubuntu side
sticks at the purple screen and doesn't go any further ?

Might just be that the installation didn't work and when doing it
through Windows it's a good idea to defragment the HD first as this
will help in the creation of the special file that Ubuntu run in when
installed in this way.

You can delete this Ubuntu file from within Windows and then run a
full defragment and try the installer again. Also make sure you have
enough free space on the HD for the size of the Ubuntu you set. Last
thing you want is to allocate so much that Windows doesn't have enough
to work with !

Are you talking about Wubu, I thought that was dropped from 12.04 or 12.10? Are
you talking about EasyBCD, or some other boot program?