If you are using Windows Vista you might be experiencing performance issues. Microsoft recently released Windows Vista Service Pack 1 which contain a performance improvement pack called Hotfix.
Alternate way to install Hotfix, download it from the link provided below.
After installing Hotfix it will improve performance for layered functions like accessing menus and low response times etc. The performance improvement are about 2 to 4 times. I feel better performance improvement for my laptop now.