IBM R40 problem

Hello I have a pretty anoying problem..
My IBM r40 is restarting or just shut's down whenever it feels like it.
I think it could be the fan but I am not sure. The fan starts sometimes just at startup but then goes dead. I've tried speedfan to try to get the fan to spin al the time but speedfan can't find the fan.
For example if I start the computer it can take like 1 min then it restarts/shut's down or It will be running for some hours before restarting so it is very different between each startup when the computer will restart. But the fan never starts.. I Tried to go into bios and find the fan but coulden't find it.
Would be very appreciated if someone could come with suggestions about what to do.

 

Replace the fan. Here's a link http://www.laptoprepairparts.com/html/LRsearchmodelresults.asp?brand=IBM&model=r40&txt=Thinkpad%20R40%20Series%20(R40,%20R40E)

 

Mogimi, please forgive my manners! Welcome to MajorGeeks! and good luck with your problem. I know that heat sink fan can be difficult to find.

 

Thanks alot