The only thing that can help somewhat is either disabling the creation of the paging file or using the customize option to increase the size to see where you are going to see the actual best performance results while trying to multitask with a single core cpu. The screen shot here shows how to go into the advanced setting when right clicking on the MyComputer icon.
The type of programs as well as the number of items that automatically startup along with Windows and run in the background will also play a role as well as keeping the system registry clean from orphan entries left there when uninstallers fail to remove everything associated with a program. One excellent freeware opens to a main window for manual removal of reg keys when going to remove a problem or the option to use the automatic cleanup method through the "tools>registry cleanup>"do them all" option seen with the RegCleaner.
http://www.majorgeeks.com/RegCleaner_d460.html
Is a lack of hard drive space causing slowdowns when there isn't enough space for the paging file? The "crap cleaner" as it referred to at it's own site is actually the CCleaner that removes useless temp folders left over from installers and other loose files on the drive that have no purpose. Be careful however if you have a habit of storing certain file types in folders you create on your own with this freeware.
http://www.ccleaner.com/
Have you defragged your hard drive lately? The analyzer will show much fragmentation is seen in percentage. Once you see it climb up it's time for that.