1. Unfortunately, you haven't told us how much RAM you have installed.. On a 32 bit version of Win 7, you could have up to 4 GB or RAM.. Do you have such? If not, make it so.

2. Shut down, or uninstall unnecessary programs running in the background.. First, if you've got lots of gadgets running, they all draw resources/memory from the system. Shut some those that you don't need.

Scanned for malware lately? If not, then download the free Malwarebytes tool from the link below and run a full system scan. Delete any malware found:

Malwarebytes Antimalware

If you've got duplicate antivirus programs running, uninstall one.. They frequently conflict and cause issues.

Also eliminate some of the unnecessary startup programs and services that don't need to be running when the computer starts up.. Both of the links below will help you weed out such.

Make your computer like the "Safe" or "Tweaked" columns in the chart in the lower section of the page below by disabling various services. (From a Run line, type "services.msc"):
http://www.blackviper.com/2010/12/17/black-vipers-windows-7-service-pack-1-service-configurations/

In a "Run" line, type: "msconfig", press OK, then select the "Startup" tab, UNCHECK those startup items that don't need to be running.. Check for each program listed at the link below:

http://www.sysinfo.org/startuplist.php

Hope this helps.

Grif