The first thing I would suggest is a defrag of your disk drive. The more you use your PC the more fragmented your hard drive gets. The more fragmented the slower.
See how much free disk space you have also. Delete any files you do not need. You may not have enough swap file space.
If you have upgraded your software then you may need more memory. The newer the program the more memory you have. The old days of writing small code is long gone.
See how much free disk space you have also. Delete any files you do not need. You may not have enough swap file space. I agree with mikesmad. Check the amount of free space on your hard drive (must be more than 10%), then run scandisk or disk doctor(Norton), delete everything under c:\windows\temp\ and all temporary internet files, then a full defrag or speedisk (Norton). Make sure you run in the most rigorous mode and consolidate your free space. Skip any surface test unless you have GRC's Spinrite.
If you have Norton Utilities or Systemworks, you can make sure it's up to date and also run a System Optimization.
These simple steps cure 90% of disk buildup slowdowns.