You have to do following case:
1) You have to check first your processor fan is working properly of not?
2) Go to Start -> Run -> then type %temp% (delete all temp files) that are increase your system speed.
3) Go to My Computer -> select all the hard disk drives i.e.(Local Disk C:,D:,E: etc) -> right click & select properties and cleanup all drives that are remove unwanted program.
4) Go to Start -> Run -> then type msconfig then click OK. It open system configuration. These go to services and start up. Then deselect the programme you don't want to run aromatically when system is start.
Note :- all changes will done in Administrator account.
5) Go to windows folder then open system32 folder look inside the name of folder is "prefetch" delete it. If you can't find the inside of system32 folder come back one step means go to windows there you will be find & delete that folder.
6) some critical problems occur from internet temp file therefore you have to clean history.
I hope your system work properly.